diff --git a/Cargo.lock b/Cargo.lock
index 0ad5033f139df..358f22463a4b2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -7746,6 +7746,7 @@ dependencies = [
  "parity-scale-codec",
  "serde",
  "sp-api",
+ "sp-blockchain",
  "sp-runtime",
  "sp-utils",
 ]
diff --git a/bin/node-template/node/src/service.rs b/bin/node-template/node/src/service.rs
index 8e57a041373a9..17606e29239bf 100644
--- a/bin/node-template/node/src/service.rs
+++ b/bin/node-template/node/src/service.rs
@@ -34,14 +34,22 @@ macro_rules! new_full_start {
 		let inherent_data_providers = sp_inherents::InherentDataProviders::new();
 
 		let builder = sc_service::ServiceBuilder::new_full::<
-			node_template_runtime::opaque::Block, node_template_runtime::RuntimeApi, crate::service::Executor
+			node_template_runtime::opaque::Block,
+			node_template_runtime::RuntimeApi,
+			crate::service::Executor
 		>($config)?
 			.with_select_chain(|_config, backend| {
 				Ok(sc_consensus::LongestChain::new(backend.clone()))
 			})?
-			.with_transaction_pool(|config, client, _fetcher, prometheus_registry| {
-				let pool_api = sc_transaction_pool::FullChainApi::new(client.clone());
-				Ok(sc_transaction_pool::BasicPool::new(config, std::sync::Arc::new(pool_api), prometheus_registry))
+			.with_transaction_pool(|builder| {
+				let pool_api = sc_transaction_pool::FullChainApi::new(
+					builder.client().clone(),
+				);
+				Ok(sc_transaction_pool::BasicPool::new(
+					builder.config().transaction_pool.clone(),
+					std::sync::Arc::new(pool_api),
+					builder.prometheus_registry(),
+				))
 			})?
 			.with_import_queue(|
 				_config,
@@ -199,13 +207,19 @@ pub fn new_light(config: Configuration) -> Result<impl AbstractService, ServiceE
 		.with_select_chain(|_config, backend| {
 			Ok(LongestChain::new(backend.clone()))
 		})?
-		.with_transaction_pool(|config, client, fetcher, prometheus_registry| {
-			let fetcher = fetcher
+		.with_transaction_pool(|builder| {
+			let fetcher = builder.fetcher()
 				.ok_or_else(|| "Trying to start light transaction pool without active fetcher")?;
 
-			let pool_api = sc_transaction_pool::LightChainApi::new(client.clone(), fetcher.clone());
+			let pool_api = sc_transaction_pool::LightChainApi::new(
+				builder.client().clone(),
+				fetcher.clone(),
+			);
 			let pool = sc_transaction_pool::BasicPool::with_revalidation_type(
-				config, Arc::new(pool_api), prometheus_registry, sc_transaction_pool::RevalidationType::Light,
+				builder.config().transaction_pool.clone(),
+				Arc::new(pool_api),
+				builder.prometheus_registry(),
+				sc_transaction_pool::RevalidationType::Light,
 			);
 			Ok(pool)
 		})?
diff --git a/bin/node/cli/src/service.rs b/bin/node/cli/src/service.rs
index 05f168bd8bad9..b1604aeedbbfa 100644
--- a/bin/node/cli/src/service.rs
+++ b/bin/node/cli/src/service.rs
@@ -53,12 +53,16 @@ macro_rules! new_full_start {
 			.with_select_chain(|_config, backend| {
 				Ok(sc_consensus::LongestChain::new(backend.clone()))
 			})?
-			.with_transaction_pool(|config, client, _fetcher, prometheus_registry| {
-				let pool_api = sc_transaction_pool::FullChainApi::new(client.clone());
+			.with_transaction_pool(|builder| {
+				let pool_api = sc_transaction_pool::FullChainApi::new(
+					builder.client().clone(),
+				);
+				let config = builder.config();
+
 				Ok(sc_transaction_pool::BasicPool::new(
-					config,
+					config.transaction_pool.clone(),
 					std::sync::Arc::new(pool_api),
-					prometheus_registry,
+					builder.prometheus_registry(),
 				))
 			})?
 			.with_import_queue(|
@@ -323,12 +327,18 @@ pub fn new_light(config: Configuration)
 		.with_select_chain(|_config, backend| {
 			Ok(LongestChain::new(backend.clone()))
 		})?
-		.with_transaction_pool(|config, client, fetcher, prometheus_registry| {
-			let fetcher = fetcher
+		.with_transaction_pool(|builder| {
+			let fetcher = builder.fetcher()
 				.ok_or_else(|| "Trying to start light transaction pool without active fetcher")?;
-			let pool_api = sc_transaction_pool::LightChainApi::new(client.clone(), fetcher.clone());
+			let pool_api = sc_transaction_pool::LightChainApi::new(
+				builder.client().clone(),
+				fetcher,
+			);
 			let pool = sc_transaction_pool::BasicPool::with_revalidation_type(
-				config, Arc::new(pool_api), prometheus_registry, sc_transaction_pool::RevalidationType::Light,
+				builder.config().transaction_pool.clone(),
+				Arc::new(pool_api),
+				builder.prometheus_registry(),
+				sc_transaction_pool::RevalidationType::Light,
 			);
 			Ok(pool)
 		})?
@@ -481,7 +491,7 @@ mod tests {
 						ChainEvent::NewBlock {
 							is_new_best: true,
 							id: parent_id.clone(),
-							retracted: vec![],
+							tree_route: None,
 							header: parent_header.clone(),
 						},
 					)
diff --git a/client/api/src/backend.rs b/client/api/src/backend.rs
index 6a7114fcc825c..9482a6118d71a 100644
--- a/client/api/src/backend.rs
+++ b/client/api/src/backend.rs
@@ -67,8 +67,10 @@ pub struct ImportSummary<Block: BlockT> {
 	pub is_new_best: bool,
 	/// Optional storage changes.
 	pub storage_changes: Option<(StorageCollection, ChildStorageCollection)>,
-	/// Blocks that got retracted because of this one got imported.
-	pub retracted: Vec<Block::Hash>,
+	/// Tree route from old best to new best.
+	///
+	/// If `None`, there was no re-org while importing.
+	pub tree_route: Option<sp_blockchain::TreeRoute<Block>>,
 }
 
 /// Import operation wrapper
diff --git a/client/api/src/client.rs b/client/api/src/client.rs
index c855cd3a08328..aa6763653d488 100644
--- a/client/api/src/client.rs
+++ b/client/api/src/client.rs
@@ -16,7 +16,7 @@
 
 //! A set of APIs supported by the client along with their primitives.
 
-use std::{fmt, collections::HashSet};
+use std::{fmt, collections::HashSet, sync::Arc};
 use sp_core::storage::StorageKey;
 use sp_runtime::{
 	traits::{Block as BlockT, NumberFor},
@@ -234,8 +234,10 @@ pub struct BlockImportNotification<Block: BlockT> {
 	pub header: Block::Header,
 	/// Is this the new best block.
 	pub is_new_best: bool,
-	/// List of retracted blocks ordered by block number.
-	pub retracted: Vec<Block::Hash>,
+	/// Tree route from old best to new best.
+	///
+	/// If `None`, there was no re-org while importing.
+	pub tree_route: Option<Arc<sp_blockchain::TreeRoute<Block>>>,
 }
 
 /// Summary of a finalized block.
diff --git a/client/basic-authorship/src/basic_authorship.rs b/client/basic-authorship/src/basic_authorship.rs
index cd241f38849a1..39ebbc89beda9 100644
--- a/client/basic-authorship/src/basic_authorship.rs
+++ b/client/basic-authorship/src/basic_authorship.rs
@@ -331,15 +331,14 @@ mod tests {
 	use parking_lot::Mutex;
 	use sp_consensus::{BlockOrigin, Proposer};
 	use substrate_test_runtime_client::{
-		prelude::*,
-		runtime::{Extrinsic, Transfer},
+		prelude::*, TestClientBuilder, runtime::{Extrinsic, Transfer}, TestClientBuilderExt,
 	};
 	use sp_transaction_pool::{ChainEvent, MaintainedTransactionPool, TransactionSource};
 	use sc_transaction_pool::{BasicPool, FullChainApi};
 	use sp_api::Core;
-	use backend::Backend;
 	use sp_blockchain::HeaderBackend;
 	use sp_runtime::traits::NumberFor;
+	use sc_client_api::Backend;
 
 	const SOURCE: TransactionSource = TransactionSource::External;
 
@@ -357,7 +356,7 @@ mod tests {
 	{
 		ChainEvent::NewBlock {
 			id: BlockId::Number(block_number.into()),
-			retracted: vec![],
+			tree_route: None,
 			is_new_best: true,
 			header,
 		}
@@ -452,8 +451,7 @@ mod tests {
 
 	#[test]
 	fn proposed_storage_changes_should_match_execute_block_storage_changes() {
-		let (client, backend) = substrate_test_runtime_client::TestClientBuilder::new()
-			.build_with_backend();
+		let (client, backend) = TestClientBuilder::new().build_with_backend();
 		let client = Arc::new(client);
 		let txpool = Arc::new(
 			BasicPool::new(
@@ -473,7 +471,9 @@ mod tests {
 		futures::executor::block_on(
 			txpool.maintain(chain_event(
 				0,
-				client.header(&BlockId::Number(0u64)).expect("header get error").expect("there should be header")
+				client.header(&BlockId::Number(0u64))
+					.expect("header get error")
+					.expect("there should be header"),
 			))
 		);
 
@@ -500,8 +500,11 @@ mod tests {
 			backend.changes_trie_storage(),
 		).unwrap();
 
-		let storage_changes = api.into_storage_changes(&state, changes_trie_state.as_ref(), genesis_hash)
-			.unwrap();
+		let storage_changes = api.into_storage_changes(
+			&state,
+			changes_trie_state.as_ref(),
+			genesis_hash,
+		).unwrap();
 
 		assert_eq!(
 			proposal.storage_changes.transaction_storage_root,
diff --git a/client/basic-authorship/src/lib.rs b/client/basic-authorship/src/lib.rs
index 63020c0e68af7..4f53c87de3979 100644
--- a/client/basic-authorship/src/lib.rs
+++ b/client/basic-authorship/src/lib.rs
@@ -25,7 +25,10 @@
 //! # use sp_consensus::{Environment, Proposer, RecordProof};
 //! # use sp_runtime::generic::BlockId;
 //! # use std::{sync::Arc, time::Duration};
-//! # use substrate_test_runtime_client::{self, runtime::{Extrinsic, Transfer}, AccountKeyring};
+//! # use substrate_test_runtime_client::{
+//! #     runtime::{Extrinsic, Transfer}, AccountKeyring,
+//! #     DefaultTestClientBuilderExt, TestClientBuilderExt,
+//! # };
 //! # use sc_transaction_pool::{BasicPool, FullChainApi};
 //! # let client = Arc::new(substrate_test_runtime_client::new());
 //! # let txpool = Arc::new(BasicPool::new(Default::default(), Arc::new(FullChainApi::new(client.clone())), None).0);
diff --git a/client/consensus/manual-seal/src/lib.rs b/client/consensus/manual-seal/src/lib.rs
index 26f493d5d220c..a5366148a7bbd 100644
--- a/client/consensus/manual-seal/src/lib.rs
+++ b/client/consensus/manual-seal/src/lib.rs
@@ -98,7 +98,7 @@ pub async fn run_manual_seal<B, CB, E, C, A, SC, S, T>(
 	inherent_data_providers: InherentDataProviders,
 )
 	where
-		A: txpool::ChainApi<Block=B, Hash=<B as BlockT>::Hash> + 'static,
+		A: txpool::ChainApi<Block=B> + 'static,
 		B: BlockT + 'static,
 		C: HeaderBackend<B> + Finalizer<B, CB> + 'static,
 		CB: ClientBackend<B> + 'static,
@@ -158,7 +158,7 @@ pub async fn run_instant_seal<B, CB, E, C, A, SC, T>(
 	inherent_data_providers: InherentDataProviders,
 )
 	where
-		A: txpool::ChainApi<Block=B, Hash=<B as BlockT>::Hash> + 'static,
+		A: txpool::ChainApi<Block=B> + 'static,
 		B: BlockT + 'static,
 		C: HeaderBackend<B> + Finalizer<B, CB> + 'static,
 		CB: ClientBackend<B> + 'static,
@@ -417,7 +417,7 @@ mod tests {
 			id: BlockId::Number(1),
 			header: client.header(&BlockId::Number(1)).expect("db error").expect("imported above"),
 			is_new_best: true,
-			retracted: vec![],
+			tree_route: None,
 		}).await;
 
 		let (tx1, rx1) = futures::channel::oneshot::channel();
diff --git a/client/consensus/manual-seal/src/seal_new_block.rs b/client/consensus/manual-seal/src/seal_new_block.rs
index a608c978e6edb..c5aea11ced316 100644
--- a/client/consensus/manual-seal/src/seal_new_block.rs
+++ b/client/consensus/manual-seal/src/seal_new_block.rs
@@ -87,7 +87,7 @@ pub async fn seal_new_block<B, SC, HB, E, T, P>(
 		E: Environment<B>,
 		<E as Environment<B>>::Error: std::fmt::Display,
 		<E::Proposer as Proposer<B>>::Error: std::fmt::Display,
-		P: txpool::ChainApi<Block=B, Hash=<B as BlockT>::Hash>,
+		P: txpool::ChainApi<Block=B>,
 		SC: SelectChain<B>,
 {
 	let future = async {
diff --git a/client/finality-grandpa/src/until_imported.rs b/client/finality-grandpa/src/until_imported.rs
index 6a39c2637eb7b..3ac94f3b062f0 100644
--- a/client/finality-grandpa/src/until_imported.rs
+++ b/client/finality-grandpa/src/until_imported.rs
@@ -585,7 +585,7 @@ mod tests {
 				origin: BlockOrigin::File,
 				header,
 				is_new_best: false,
-				retracted: vec![],
+				tree_route: None,
 			}).unwrap();
 		}
 	}
diff --git a/client/offchain/src/lib.rs b/client/offchain/src/lib.rs
index 332e9f779a8e2..d6e62501b6bd8 100644
--- a/client/offchain/src/lib.rs
+++ b/client/offchain/src/lib.rs
@@ -166,7 +166,7 @@ mod tests {
 	use super::*;
 	use std::sync::Arc;
 	use sc_network::{Multiaddr, PeerId};
-	use substrate_test_runtime_client::runtime::Block;
+	use substrate_test_runtime_client::{TestClient, runtime::Block};
 	use sc_transaction_pool::{BasicPool, FullChainApi};
 	use sp_transaction_pool::{TransactionPool, InPoolTransaction};
 	use sc_client_api::ExecutorProvider;
@@ -183,7 +183,9 @@ mod tests {
 		}
 	}
 
-	struct TestPool(BasicPool<FullChainApi<substrate_test_runtime_client::TestClient, Block>, Block>);
+	struct TestPool(
+		BasicPool<FullChainApi<TestClient, Block>, Block>
+	);
 
 	impl sp_transaction_pool::OffchainSubmitTransaction<Block> for TestPool {
 		fn submit_at(
@@ -200,8 +202,8 @@ mod tests {
 
 	#[test]
 	fn should_call_into_runtime_and_produce_extrinsic() {
-		// given
 		let _ = env_logger::try_init();
+
 		let client = Arc::new(substrate_test_runtime_client::new());
 		let pool = Arc::new(TestPool(BasicPool::new(
 			Default::default(),
diff --git a/client/rpc/src/author/tests.rs b/client/rpc/src/author/tests.rs
index 8c1b82028bd79..d70a2ce2aff99 100644
--- a/client/rpc/src/author/tests.rs
+++ b/client/rpc/src/author/tests.rs
@@ -58,11 +58,9 @@ struct TestSetup {
 impl Default for TestSetup {
 	fn default() -> Self {
 		let keystore = KeyStore::new();
-		let client = Arc::new(
-			substrate_test_runtime_client::TestClientBuilder::new()
-				.set_keystore(keystore.clone())
-				.build()
-		);
+		let client_builder = substrate_test_runtime_client::TestClientBuilder::new();
+		let client = Arc::new(client_builder.set_keystore(keystore.clone()).build());
+
 		let pool = Arc::new(BasicPool::new(
 			Default::default(),
 			Arc::new(FullChainApi::new(client.clone())),
diff --git a/client/service/src/builder.rs b/client/service/src/builder.rs
index baf1c2e0cceff..c2af1a129bd5f 100644
--- a/client/service/src/builder.rs
+++ b/client/service/src/builder.rs
@@ -16,16 +16,17 @@
 // You should have received a copy of the GNU General Public License
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
-use crate::{Service, NetworkStatus, NetworkState, error::Error, DEFAULT_PROTOCOL_ID, MallocSizeOfWasm};
-use crate::{start_rpc_servers, build_network_future, TransactionPoolAdapter, TaskManager, SpawnTaskHandle};
-use crate::status_sinks;
-use crate::config::{Configuration, KeystoreConfig, PrometheusConfig, OffchainWorkerConfig};
-use crate::metrics::MetricsService;
+use crate::{
+	Service, NetworkStatus, NetworkState, error::Error, DEFAULT_PROTOCOL_ID, MallocSizeOfWasm,
+	start_rpc_servers, build_network_future, TransactionPoolAdapter, TaskManager, SpawnTaskHandle,
+	status_sinks, metrics::MetricsService, client::{Client, ClientConfig},
+	config::{Configuration, KeystoreConfig, PrometheusConfig, OffchainWorkerConfig},
+};
 use sc_client_api::{
-	self, BlockchainEvents, backend::RemoteBackend, light::RemoteBlockchain, execution_extensions::ExtensionsFactory,
-	ExecutorProvider, CallExecutor, ForkBlocks, BadBlocks, CloneableSpawn, UsageProvider,
+	BlockchainEvents, backend::RemoteBackend, light::RemoteBlockchain,
+	execution_extensions::ExtensionsFactory, ExecutorProvider, CallExecutor, ForkBlocks, BadBlocks,
+	CloneableSpawn, UsageProvider,
 };
-use crate::client::{Client, ClientConfig};
 use sp_utils::mpsc::{tracing_unbounded, TracingUnboundedSender};
 use sc_chain_spec::get_extension;
 use sp_consensus::{
@@ -55,7 +56,6 @@ use std::{
 use wasm_timer::SystemTime;
 use sc_telemetry::{telemetry, SUBSTRATE_INFO};
 use sp_transaction_pool::{MaintainedTransactionPool, ChainEvent};
-use sp_blockchain;
 use prometheus_endpoint::Registry;
 use sc_client_db::{Backend, DatabaseSettings};
 use sp_core::traits::CodeExecutor;
@@ -452,8 +452,29 @@ impl ServiceBuilder<(), (), (), (), (), (), (), (), (), (), ()> {
 }
 
 impl<TBl, TRtApi, TCl, TFchr, TSc, TImpQu, TFprb, TFpp, TExPool, TRpc, Backend>
-	ServiceBuilder<TBl, TRtApi, TCl, TFchr, TSc, TImpQu, TFprb, TFpp,
-	 	TExPool, TRpc, Backend> {
+	ServiceBuilder<
+		TBl,
+		TRtApi,
+		TCl,
+		TFchr,
+		TSc,
+		TImpQu,
+		TFprb,
+		TFpp,
+		TExPool,
+		TRpc,
+		Backend
+	>
+{
+	/// Returns a reference to the configuration that was stored in this builder.
+	pub fn config(&self) -> &Configuration {
+		&self.config
+	}
+
+	/// Returns a reference to the optional prometheus registry that was stored in this builder.
+	pub fn prometheus_registry(&self) -> Option<&Registry> {
+		self.config.prometheus_config.as_ref().map(|config| &config.registry)
+	}
 
 	/// Returns a reference to the client that was stored in this builder.
 	pub fn client(&self) -> &Arc<TCl> {
@@ -698,20 +719,12 @@ impl<TBl, TRtApi, TCl, TFchr, TSc, TImpQu, TFprb, TFpp, TExPool, TRpc, Backend>
 	pub fn with_transaction_pool<UExPool>(
 		self,
 		transaction_pool_builder: impl FnOnce(
-			sc_transaction_pool::txpool::Options,
-			Arc<TCl>,
-			Option<TFchr>,
-			Option<&Registry>,
-		) -> Result<(UExPool, Option<BackgroundTask>), Error>
+			&Self,
+		) -> Result<(UExPool, Option<BackgroundTask>), Error>,
 	) -> Result<ServiceBuilder<TBl, TRtApi, TCl, TFchr, TSc, TImpQu, TFprb, TFpp,
 		UExPool, TRpc, Backend>, Error>
 	where TSc: Clone, TFchr: Clone {
-		let (transaction_pool, background_task) = transaction_pool_builder(
-			self.config.transaction_pool.clone(),
-			self.client.clone(),
-			self.fetcher.clone(),
-			self.config.prometheus_config.as_ref().map(|config| &config.registry),
-		)?;
+		let (transaction_pool, background_task) = transaction_pool_builder(&self)?;
 
 		if let Some(background_task) = background_task{
 			self.task_manager.spawn_handle().spawn("txpool-background", background_task);
@@ -1032,7 +1045,7 @@ ServiceBuilder<
 			let mut import_stream = client.import_notification_stream().map(|n| ChainEvent::NewBlock {
 				id: BlockId::Hash(n.hash),
 				header: n.header,
-				retracted: n.retracted,
+				tree_route: n.tree_route,
 				is_new_best: n.is_new_best,
 			}).fuse();
 			let mut finality_stream = client.finality_notification_stream()
@@ -1349,7 +1362,7 @@ ServiceBuilder<
 			_telemetry_on_connect_sinks: telemetry_connection_sinks.clone(),
 			keystore,
 			marker: PhantomData::<TBl>,
-			prometheus_registry: config.prometheus_config.map(|config| config.registry)
+			prometheus_registry: config.prometheus_config.map(|config| config.registry),
 		})
 	}
 }
diff --git a/client/service/src/client/client.rs b/client/service/src/client/client.rs
index 77b3f065f43dd..fcbaab885134c 100644
--- a/client/service/src/client/client.rs
+++ b/client/service/src/client/client.rs
@@ -787,15 +787,15 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 			NewBlockState::Normal
 		};
 
-		let retracted = if is_new_best {
+		let tree_route = if is_new_best {
 			let route_from_best = sp_blockchain::tree_route(
 				self.backend.blockchain(),
 				info.best_hash,
 				parent_hash,
 			)?;
-			route_from_best.retracted().iter().rev().map(|e| e.hash.clone()).collect()
+			Some(route_from_best)
 		} else {
-			Vec::default()
+			None
 		};
 
 		trace!(
@@ -826,7 +826,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 				header: import_headers.into_post(),
 				is_new_best,
 				storage_changes,
-				retracted,
+				tree_route,
 			})
 		}
 
@@ -1048,7 +1048,7 @@ impl<B, E, Block, RA> Client<B, E, Block, RA> where
 			origin: notify_import.origin,
 			header: notify_import.header,
 			is_new_best: notify_import.is_new_best,
-			retracted: notify_import.retracted,
+			tree_route: notify_import.tree_route.map(Arc::new),
 		};
 
 		self.import_notification_sinks.lock()
diff --git a/client/transaction-pool/graph/benches/basics.rs b/client/transaction-pool/graph/benches/basics.rs
index ee92b60d548e6..bb10086bd4a55 100644
--- a/client/transaction-pool/graph/benches/basics.rs
+++ b/client/transaction-pool/graph/benches/basics.rs
@@ -51,7 +51,6 @@ fn to_tag(nonce: u64, from: AccountId) -> Tag {
 
 impl ChainApi for TestApi {
 	type Block = Block;
-	type Hash = H256;
 	type Error = sp_transaction_pool::error::Error;
 	type ValidationFuture = Ready<sp_transaction_pool::error::Result<TransactionValidity>>;
 	type BodyFuture = Ready<sp_transaction_pool::error::Result<Option<Vec<Extrinsic>>>>;
@@ -107,7 +106,7 @@ impl ChainApi for TestApi {
 		})
 	}
 
-	fn hash_and_length(&self, uxt: &ExtrinsicFor<Self>) -> (Self::Hash, usize) {
+	fn hash_and_length(&self, uxt: &ExtrinsicFor<Self>) -> (H256, usize) {
 		let encoded = uxt.encode();
 		(blake2_256(&encoded).into(), encoded.len())
 	}
diff --git a/client/transaction-pool/graph/src/lib.rs b/client/transaction-pool/graph/src/lib.rs
index 04e5d0d3fbe9f..b4646c6055bf6 100644
--- a/client/transaction-pool/graph/src/lib.rs
+++ b/client/transaction-pool/graph/src/lib.rs
@@ -38,8 +38,6 @@ pub mod watcher;
 
 pub use self::base_pool::Transaction;
 pub use self::pool::{
-	Pool,
-	Options, ChainApi, EventStream, ExtrinsicFor,
-	BlockHash, ExHash, NumberFor, TransactionFor,
-	ValidatedTransaction,
+	Pool, Options, ChainApi, EventStream, ExtrinsicFor, ExtrinsicHash,
+	BlockHash, NumberFor, TransactionFor, ValidatedTransaction,
 };
diff --git a/client/transaction-pool/graph/src/listener.rs b/client/transaction-pool/graph/src/listener.rs
index 2923f2b34a8d0..1bc3720fa6b85 100644
--- a/client/transaction-pool/graph/src/listener.rs
+++ b/client/transaction-pool/graph/src/listener.rs
@@ -22,14 +22,14 @@ use std::{
 };
 use linked_hash_map::LinkedHashMap;
 use serde::Serialize;
-use crate::{watcher, ChainApi, BlockHash};
+use crate::{watcher, ChainApi, ExtrinsicHash, BlockHash};
 use log::{debug, trace, warn};
 use sp_runtime::traits;
 
 /// Extrinsic pool default listener.
-pub struct Listener<H: hash::Hash + Eq + Debug, C: ChainApi> {
-	watchers: HashMap<H, watcher::Sender<H, BlockHash<C>>>,
-	finality_watchers: LinkedHashMap<BlockHash<C>, Vec<H>>,
+pub struct Listener<H: hash::Hash + Eq, C: ChainApi> {
+	watchers: HashMap<H, watcher::Sender<H, ExtrinsicHash<C>>>,
+	finality_watchers: LinkedHashMap<ExtrinsicHash<C>, Vec<H>>,
 }
 
 /// Maximum number of blocks awaiting finality at any time.
@@ -45,7 +45,7 @@ impl<H: hash::Hash + Eq + Debug, C: ChainApi> Default for Listener<H, C> {
 }
 
 impl<H: hash::Hash + traits::Member + Serialize, C: ChainApi> Listener<H, C> {
-	fn fire<F>(&mut self, hash: &H, fun: F) where F: FnOnce(&mut watcher::Sender<H, BlockHash<C>>) {
+	fn fire<F>(&mut self, hash: &H, fun: F) where F: FnOnce(&mut watcher::Sender<H, ExtrinsicHash<C>>) {
 		let clean = if let Some(h) = self.watchers.get_mut(hash) {
 			fun(h);
 			h.is_done()
@@ -61,7 +61,7 @@ impl<H: hash::Hash + traits::Member + Serialize, C: ChainApi> Listener<H, C> {
 	/// Creates a new watcher for given verified extrinsic.
 	///
 	/// The watcher can be used to subscribe to life-cycle events of that extrinsic.
-	pub fn create_watcher(&mut self, hash: H) -> watcher::Watcher<H, BlockHash<C>> {
+	pub fn create_watcher(&mut self, hash: H) -> watcher::Watcher<H, ExtrinsicHash<C>> {
 		let sender = self.watchers.entry(hash.clone()).or_insert_with(watcher::Sender::default);
 		sender.new_watcher(hash)
 	}
diff --git a/client/transaction-pool/graph/src/pool.rs b/client/transaction-pool/graph/src/pool.rs
index 4f41e9110915e..e4d81c38ae38e 100644
--- a/client/transaction-pool/graph/src/pool.rs
+++ b/client/transaction-pool/graph/src/pool.rs
@@ -17,19 +17,16 @@
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
 use std::{
-	hash,
 	collections::HashMap,
 	sync::Arc,
 };
 
-use crate::base_pool as base;
-use crate::watcher::Watcher;
-use serde::Serialize;
+use crate::{base_pool as base, watcher::Watcher};
 
 use futures::{Future, FutureExt};
 use sp_runtime::{
 	generic::BlockId,
-	traits::{self, SaturatedConversion},
+	traits::{self, SaturatedConversion, Block as BlockT},
 	transaction_validity::{
 		TransactionValidity, TransactionTag as Tag, TransactionValidityError, TransactionSource,
 	},
@@ -44,19 +41,19 @@ pub use crate::validated_pool::ValidatedTransaction;
 /// Modification notification event stream type;
 pub type EventStream<H> = TracingUnboundedReceiver<H>;
 
-/// Extrinsic hash type for a pool.
-pub type ExHash<A> = <A as ChainApi>::Hash;
 /// Block hash type for a pool.
 pub type BlockHash<A> = <<A as ChainApi>::Block as traits::Block>::Hash;
+/// Extrinsic hash type for a pool.
+pub type ExtrinsicHash<A> = <<A as ChainApi>::Block as traits::Block>::Hash;
 /// Extrinsic type for a pool.
 pub type ExtrinsicFor<A> = <<A as ChainApi>::Block as traits::Block>::Extrinsic;
 /// Block number type for the ChainApi
 pub type NumberFor<A> = traits::NumberFor<<A as ChainApi>::Block>;
 /// A type of transaction stored in the pool
-pub type TransactionFor<A> = Arc<base::Transaction<ExHash<A>, ExtrinsicFor<A>>>;
+pub type TransactionFor<A> = Arc<base::Transaction<ExtrinsicHash<A>, ExtrinsicFor<A>>>;
 /// A type of validated transaction stored in the pool.
 pub type ValidatedTransactionFor<A> = ValidatedTransaction<
-	ExHash<A>,
+	ExtrinsicHash<A>,
 	ExtrinsicFor<A>,
 	<A as ChainApi>::Error,
 >;
@@ -64,15 +61,15 @@ pub type ValidatedTransactionFor<A> = ValidatedTransaction<
 /// Concrete extrinsic validation and query logic.
 pub trait ChainApi: Send + Sync {
 	/// Block type.
-	type Block: traits::Block;
-	/// Transaction Hash type
-	type Hash: hash::Hash + Eq + traits::Member + Serialize;
+	type Block: BlockT;
 	/// Error type.
 	type Error: From<error::Error> + error::IntoPoolError;
 	/// Validate transaction future.
 	type ValidationFuture: Future<Output=Result<TransactionValidity, Self::Error>> + Send + Unpin;
 	/// Body future (since block body might be remote)
-	type BodyFuture: Future<Output = Result<Option<Vec<<Self::Block as traits::Block>::Extrinsic>>, Self::Error>> + Unpin + Send + 'static;
+	type BodyFuture: Future<
+		Output = Result<Option<Vec<<Self::Block as traits::Block>::Extrinsic>>, Self::Error>
+	> + Unpin + Send + 'static;
 
 	/// Verify extrinsic at given block.
 	fn validate_transaction(
@@ -83,13 +80,19 @@ pub trait ChainApi: Send + Sync {
 	) -> Self::ValidationFuture;
 
 	/// Returns a block number given the block id.
-	fn block_id_to_number(&self, at: &BlockId<Self::Block>) -> Result<Option<NumberFor<Self>>, Self::Error>;
+	fn block_id_to_number(
+		&self,
+		at: &BlockId<Self::Block>,
+	) -> Result<Option<NumberFor<Self>>, Self::Error>;
 
 	/// Returns a block hash given the block id.
-	fn block_id_to_hash(&self, at: &BlockId<Self::Block>) -> Result<Option<BlockHash<Self>>, Self::Error>;
+	fn block_id_to_hash(
+		&self,
+		at: &BlockId<Self::Block>,
+	) -> Result<Option<<Self::Block as BlockT>::Hash>, Self::Error>;
 
 	/// Returns hash and encoding length of the extrinsic.
-	fn hash_and_length(&self, uxt: &ExtrinsicFor<Self>) -> (Self::Hash, usize);
+	fn hash_and_length(&self, uxt: &ExtrinsicFor<Self>) -> (ExtrinsicHash<Self>, usize);
 
 	/// Returns a block body given the block id.
 	fn block_body(&self, at: &BlockId<Self::Block>) -> Self::BodyFuture;
@@ -130,7 +133,6 @@ pub struct Pool<B: ChainApi> {
 #[cfg(not(target_os = "unknown"))]
 impl<B: ChainApi> parity_util_mem::MallocSizeOf for Pool<B>
 where
-	B::Hash: parity_util_mem::MallocSizeOf,
 	ExtrinsicFor<B>: parity_util_mem::MallocSizeOf,
 {
 	fn size_of(&self, ops: &mut parity_util_mem::MallocSizeOfOps) -> usize {
@@ -153,7 +155,7 @@ impl<B: ChainApi> Pool<B> {
 		source: TransactionSource,
 		xts: T,
 		force: bool,
-	) -> Result<Vec<Result<ExHash<B>, B::Error>>, B::Error> where
+	) -> Result<Vec<Result<ExtrinsicHash<B>, B::Error>>, B::Error> where
 		T: IntoIterator<Item=ExtrinsicFor<B>>,
 	{
 		let validated_pool = self.validated_pool.clone();
@@ -172,7 +174,7 @@ impl<B: ChainApi> Pool<B> {
 		at: &BlockId<B::Block>,
 		source: TransactionSource,
 		xt: ExtrinsicFor<B>,
-	) -> Result<ExHash<B>, B::Error> {
+	) -> Result<ExtrinsicHash<B>, B::Error> {
 		self.submit_at(at, source, std::iter::once(xt), false)
 			.map(|import_result| import_result.and_then(|mut import_result| import_result
 				.pop()
@@ -187,7 +189,7 @@ impl<B: ChainApi> Pool<B> {
 		at: &BlockId<B::Block>,
 		source: TransactionSource,
 		xt: ExtrinsicFor<B>,
-	) -> Result<Watcher<ExHash<B>, BlockHash<B>>, B::Error> {
+	) -> Result<Watcher<ExtrinsicHash<B>, ExtrinsicHash<B>>, B::Error> {
 		let block_number = self.resolve_block_number(at)?;
 		let (_, tx) = self.verify_one(
 			at, block_number, source, xt, false
@@ -198,7 +200,7 @@ impl<B: ChainApi> Pool<B> {
 	/// Resubmit some transaction that were validated elsewhere.
 	pub fn resubmit(
 		&self,
-		revalidated_transactions: HashMap<ExHash<B>, ValidatedTransactionFor<B>>,
+		revalidated_transactions: HashMap<ExtrinsicHash<B>, ValidatedTransactionFor<B>>,
 	) {
 
 		let now = Instant::now();
@@ -215,7 +217,11 @@ impl<B: ChainApi> Pool<B> {
 	/// Used to clear the pool from transactions that were part of recently imported block.
 	/// The main difference from the `prune` is that we do not revalidate any transactions
 	/// and ignore unknown passed hashes.
-	pub fn prune_known(&self, at: &BlockId<B::Block>, hashes: &[ExHash<B>]) -> Result<(), B::Error> {
+	pub fn prune_known(
+		&self,
+		at: &BlockId<B::Block>,
+		hashes: &[ExtrinsicHash<B>],
+	) -> Result<(), B::Error> {
 		// Get details of all extrinsics that are already in the pool
 		let in_pool_tags = self.validated_pool.extrinsics_tags(hashes)
 			.into_iter().filter_map(|x| x).flat_map(|x| x);
@@ -299,7 +305,7 @@ impl<B: ChainApi> Pool<B> {
 		&self,
 		at: &BlockId<B::Block>,
 		tags: impl IntoIterator<Item=Tag>,
-		known_imported_hashes: impl IntoIterator<Item=ExHash<B>> + Clone,
+		known_imported_hashes: impl IntoIterator<Item=ExtrinsicHash<B>> + Clone,
 	) -> Result<(), B::Error> {
 		log::debug!(target: "txpool", "Pruning at {:?}", at);
 		// Prune all transactions that provide given tags
@@ -336,7 +342,7 @@ impl<B: ChainApi> Pool<B> {
 	}
 
 	/// Returns transaction hash
-	pub fn hash_of(&self, xt: &ExtrinsicFor<B>) -> ExHash<B> {
+	pub fn hash_of(&self, xt: &ExtrinsicFor<B>) -> ExtrinsicHash<B> {
 		self.validated_pool.api().hash_and_length(xt).0
 	}
 
@@ -353,7 +359,7 @@ impl<B: ChainApi> Pool<B> {
 		at: &BlockId<B::Block>,
 		xts: impl IntoIterator<Item=(TransactionSource, ExtrinsicFor<B>)>,
 		force: bool,
-	) -> Result<HashMap<ExHash<B>, ValidatedTransactionFor<B>>, B::Error> {
+	) -> Result<HashMap<ExtrinsicHash<B>, ValidatedTransactionFor<B>>, B::Error> {
 		// we need a block number to compute tx validity
 		let block_number = self.resolve_block_number(at)?;
 		let mut result = HashMap::new();
@@ -379,7 +385,7 @@ impl<B: ChainApi> Pool<B> {
 		source: TransactionSource,
 		xt: ExtrinsicFor<B>,
 		force: bool,
-	) -> (ExHash<B>, ValidatedTransactionFor<B>) {
+	) -> (ExtrinsicHash<B>, ValidatedTransactionFor<B>) {
 		let (hash, bytes) = self.validated_pool.api().hash_and_length(&xt);
 		if !force && self.validated_pool.is_banned(&hash) {
 			return (
@@ -444,9 +450,12 @@ mod tests {
 	use futures::executor::block_on;
 	use super::*;
 	use sp_transaction_pool::TransactionStatus;
-	use sp_runtime::transaction_validity::{ValidTransaction, InvalidTransaction, TransactionSource};
+	use sp_runtime::{
+		traits::Hash,
+		transaction_validity::{ValidTransaction, InvalidTransaction, TransactionSource},
+	};
 	use codec::Encode;
-	use substrate_test_runtime::{Block, Extrinsic, Transfer, H256, AccountId};
+	use substrate_test_runtime::{Block, Extrinsic, Transfer, H256, AccountId, Hashing};
 	use assert_matches::assert_matches;
 	use wasm_timer::Instant;
 	use crate::base_pool::Limit;
@@ -457,14 +466,13 @@ mod tests {
 	#[derive(Clone, Debug, Default)]
 	struct TestApi {
 		delay: Arc<Mutex<Option<std::sync::mpsc::Receiver<()>>>>,
-		invalidate: Arc<Mutex<HashSet<u64>>>,
-		clear_requirements: Arc<Mutex<HashSet<u64>>>,
-		add_requirements: Arc<Mutex<HashSet<u64>>>,
+		invalidate: Arc<Mutex<HashSet<H256>>>,
+		clear_requirements: Arc<Mutex<HashSet<H256>>>,
+		add_requirements: Arc<Mutex<HashSet<H256>>>,
 	}
 
 	impl ChainApi for TestApi {
 		type Block = Block;
-		type Hash = u64;
 		type Error = error::Error;
 		type ValidationFuture = futures::future::Ready<error::Result<TransactionValidity>>;
 		type BodyFuture = futures::future::Ready<error::Result<Option<Vec<Extrinsic>>>>;
@@ -518,7 +526,10 @@ mod tests {
 		}
 
 		/// Returns a block number given the block id.
-		fn block_id_to_number(&self, at: &BlockId<Self::Block>) -> Result<Option<NumberFor<Self>>, Self::Error> {
+		fn block_id_to_number(
+			&self,
+			at: &BlockId<Self::Block>,
+		) -> Result<Option<NumberFor<Self>>, Self::Error> {
 			Ok(match at {
 				BlockId::Number(num) => Some(*num),
 				BlockId::Hash(_) => None,
@@ -526,7 +537,10 @@ mod tests {
 		}
 
 		/// Returns a block hash given the block id.
-		fn block_id_to_hash(&self, at: &BlockId<Self::Block>) -> Result<Option<BlockHash<Self>>, Self::Error> {
+		fn block_id_to_hash(
+			&self,
+			at: &BlockId<Self::Block>,
+		) -> Result<Option<<Self::Block as BlockT>::Hash>, Self::Error> {
 			Ok(match at {
 				BlockId::Number(num) => Some(H256::from_low_u64_be(*num)).into(),
 				BlockId::Hash(_) => None,
@@ -534,12 +548,10 @@ mod tests {
 		}
 
 		/// Hash the extrinsic.
-		fn hash_and_length(&self, uxt: &ExtrinsicFor<Self>) -> (Self::Hash, usize) {
-			let len = uxt.encode().len();
-			(
-				(H256::from(uxt.transfer().from.clone()).to_low_u64_be() << 5) + uxt.transfer().nonce,
-				len
-			)
+		fn hash_and_length(&self, uxt: &ExtrinsicFor<Self>) -> (BlockHash<Self>, usize) {
+			let encoded = uxt.encode();
+			let len = encoded.len();
+			(Hashing::hash(&encoded), len)
 		}
 
 		fn block_body(&self, _id: &BlockId<Self::Block>) -> Self::BodyFuture {
@@ -599,19 +611,19 @@ mod tests {
 
 	#[test]
 	fn should_notify_about_pool_events() {
-		let stream = {
+		let (stream, hash0, hash1) = {
 			// given
 			let pool = pool();
 			let stream = pool.validated_pool().import_notification_stream();
 
 			// when
-			let _hash = block_on(pool.submit_one(&BlockId::Number(0), SOURCE, uxt(Transfer {
+			let hash0 = block_on(pool.submit_one(&BlockId::Number(0), SOURCE, uxt(Transfer {
 				from: AccountId::from_h256(H256::from_low_u64_be(1)),
 				to: AccountId::from_h256(H256::from_low_u64_be(2)),
 				amount: 5,
 				nonce: 0,
 			}))).unwrap();
-			let _hash = block_on(pool.submit_one(&BlockId::Number(0), SOURCE, uxt(Transfer {
+			let hash1 = block_on(pool.submit_one(&BlockId::Number(0), SOURCE, uxt(Transfer {
 				from: AccountId::from_h256(H256::from_low_u64_be(1)),
 				to: AccountId::from_h256(H256::from_low_u64_be(2)),
 				amount: 5,
@@ -627,13 +639,14 @@ mod tests {
 
 			assert_eq!(pool.validated_pool().status().ready, 2);
 			assert_eq!(pool.validated_pool().status().future, 1);
-			stream
+
+			(stream, hash0, hash1)
 		};
 
 		// then
 		let mut it = futures::executor::block_on_stream(stream);
-		assert_eq!(it.next(), Some(32));
-		assert_eq!(it.next(), Some(33));
+		assert_eq!(it.next(), Some(hash0));
+		assert_eq!(it.next(), Some(hash1));
 		assert_eq!(it.next(), None);
 	}
 
@@ -795,7 +808,10 @@ mod tests {
 			// then
 			let mut stream = futures::executor::block_on_stream(watcher.into_stream());
 			assert_eq!(stream.next(), Some(TransactionStatus::Ready));
-			assert_eq!(stream.next(), Some(TransactionStatus::InBlock(H256::from_low_u64_be(2).into())));
+			assert_eq!(
+				stream.next(),
+				Some(TransactionStatus::InBlock(H256::from_low_u64_be(2).into())),
+			);
 		}
 
 		#[test]
@@ -812,14 +828,19 @@ mod tests {
 			assert_eq!(pool.validated_pool().status().future, 0);
 
 			// when
-			block_on(pool.prune_tags(&BlockId::Number(2), vec![vec![0u8]], vec![2u64])).unwrap();
+			block_on(
+				pool.prune_tags(&BlockId::Number(2), vec![vec![0u8]], vec![watcher.hash().clone()]),
+			).unwrap();
 			assert_eq!(pool.validated_pool().status().ready, 0);
 			assert_eq!(pool.validated_pool().status().future, 0);
 
 			// then
 			let mut stream = futures::executor::block_on_stream(watcher.into_stream());
 			assert_eq!(stream.next(), Some(TransactionStatus::Ready));
-			assert_eq!(stream.next(), Some(TransactionStatus::InBlock(H256::from_low_u64_be(2).into())));
+			assert_eq!(
+				stream.next(),
+				Some(TransactionStatus::InBlock(H256::from_low_u64_be(2).into())),
+			);
 		}
 
 		#[test]
diff --git a/client/transaction-pool/graph/src/validated_pool.rs b/client/transaction-pool/graph/src/validated_pool.rs
index 9ab45e3b263c0..d730b892e3502 100644
--- a/client/transaction-pool/graph/src/validated_pool.rs
+++ b/client/transaction-pool/graph/src/validated_pool.rs
@@ -22,7 +22,7 @@ use std::{
 	sync::Arc,
 };
 
-use crate::{base_pool as base, BlockHash};
+use crate::base_pool as base;
 use crate::listener::Listener;
 use crate::rotator::PoolRotator;
 use crate::watcher::Watcher;
@@ -39,7 +39,9 @@ use wasm_timer::Instant;
 use sp_utils::mpsc::{tracing_unbounded, TracingUnboundedSender};
 
 use crate::base_pool::PruneStatus;
-use crate::pool::{EventStream, Options, ChainApi, ExHash, ExtrinsicFor, TransactionFor};
+use crate::pool::{
+	EventStream, Options, ChainApi, BlockHash, ExtrinsicHash, ExtrinsicFor, TransactionFor,
+};
 
 /// Pre-validated transaction. Validated pool only accepts transactions wrapped in this enum.
 #[derive(Debug)]
@@ -82,7 +84,7 @@ impl<Hash, Ex, Error> ValidatedTransaction<Hash, Ex, Error> {
 
 /// A type of validated transaction stored in the pool.
 pub type ValidatedTransactionFor<B> = ValidatedTransaction<
-	ExHash<B>,
+	ExtrinsicHash<B>,
 	ExtrinsicFor<B>,
 	<B as ChainApi>::Error,
 >;
@@ -91,19 +93,18 @@ pub type ValidatedTransactionFor<B> = ValidatedTransaction<
 pub struct ValidatedPool<B: ChainApi> {
 	api: Arc<B>,
 	options: Options,
-	listener: RwLock<Listener<ExHash<B>, B>>,
+	listener: RwLock<Listener<ExtrinsicHash<B>, B>>,
 	pool: RwLock<base::BasePool<
-		ExHash<B>,
+		ExtrinsicHash<B>,
 		ExtrinsicFor<B>,
 	>>,
-	import_notification_sinks: Mutex<Vec<TracingUnboundedSender<ExHash<B>>>>,
-	rotator: PoolRotator<ExHash<B>>,
+	import_notification_sinks: Mutex<Vec<TracingUnboundedSender<ExtrinsicHash<B>>>>,
+	rotator: PoolRotator<ExtrinsicHash<B>>,
 }
 
 #[cfg(not(target_os = "unknown"))]
 impl<B: ChainApi> parity_util_mem::MallocSizeOf for ValidatedPool<B>
 where
-	B::Hash: parity_util_mem::MallocSizeOf,
 	ExtrinsicFor<B>: parity_util_mem::MallocSizeOf,
 {
 	fn size_of(&self, ops: &mut parity_util_mem::MallocSizeOfOps) -> usize {
@@ -127,17 +128,17 @@ impl<B: ChainApi> ValidatedPool<B> {
 	}
 
 	/// Bans given set of hashes.
-	pub fn ban(&self, now: &Instant, hashes: impl IntoIterator<Item=ExHash<B>>) {
+	pub fn ban(&self, now: &Instant, hashes: impl IntoIterator<Item=ExtrinsicHash<B>>) {
 		self.rotator.ban(now, hashes)
 	}
 
 	/// Returns true if transaction with given hash is currently banned from the pool.
-	pub fn is_banned(&self, hash: &ExHash<B>) -> bool {
+	pub fn is_banned(&self, hash: &ExtrinsicHash<B>) -> bool {
 		self.rotator.is_banned(hash)
 	}
 
 	/// Imports a bunch of pre-validated transactions to the pool.
-	pub fn submit<T>(&self, txs: T) -> Vec<Result<ExHash<B>, B::Error>> where
+	pub fn submit<T>(&self, txs: T) -> Vec<Result<ExtrinsicHash<B>, B::Error>> where
 		T: IntoIterator<Item=ValidatedTransactionFor<B>>
 	{
 		let results = txs.into_iter()
@@ -158,7 +159,7 @@ impl<B: ChainApi> ValidatedPool<B> {
 	}
 
 	/// Submit single pre-validated transaction to the pool.
-	fn submit_one(&self, tx: ValidatedTransactionFor<B>) -> Result<ExHash<B>, B::Error> {
+	fn submit_one(&self, tx: ValidatedTransactionFor<B>) -> Result<ExtrinsicHash<B>, B::Error> {
 		match tx {
 			ValidatedTransaction::Valid(tx) => {
 				let imported = self.pool.write().import(tx)?;
@@ -183,7 +184,7 @@ impl<B: ChainApi> ValidatedPool<B> {
 		}
 	}
 
-	fn enforce_limits(&self) -> HashSet<ExHash<B>> {
+	fn enforce_limits(&self) -> HashSet<ExtrinsicHash<B>> {
 		let status = self.pool.read().status();
 		let ready_limit = &self.options.ready;
 		let future_limit = &self.options.future;
@@ -228,7 +229,7 @@ impl<B: ChainApi> ValidatedPool<B> {
 	pub fn submit_and_watch(
 		&self,
 		tx: ValidatedTransactionFor<B>,
-	) -> Result<Watcher<ExHash<B>, BlockHash<B>>, B::Error> {
+	) -> Result<Watcher<ExtrinsicHash<B>, ExtrinsicHash<B>>, B::Error> {
 		match tx {
 			ValidatedTransaction::Valid(tx) => {
 				let hash = self.api.hash_and_length(&tx.data).0;
@@ -250,7 +251,7 @@ impl<B: ChainApi> ValidatedPool<B> {
 	///
 	/// Removes and then submits passed transactions and all dependent transactions.
 	/// Transactions that are missing from the pool are not submitted.
-	pub fn resubmit(&self, mut updated_transactions: HashMap<ExHash<B>, ValidatedTransactionFor<B>>) {
+	pub fn resubmit(&self, mut updated_transactions: HashMap<ExtrinsicHash<B>, ValidatedTransactionFor<B>>) {
 		#[derive(Debug, Clone, Copy, PartialEq)]
 		enum Status { Future, Ready, Failed, Dropped };
 
@@ -369,7 +370,7 @@ impl<B: ChainApi> ValidatedPool<B> {
 	}
 
 	/// For each extrinsic, returns tags that it provides (if known), or None (if it is unknown).
-	pub fn extrinsics_tags(&self, hashes: &[ExHash<B>]) -> Vec<Option<Vec<Tag>>> {
+	pub fn extrinsics_tags(&self, hashes: &[ExtrinsicHash<B>]) -> Vec<Option<Vec<Tag>>> {
 		self.pool.read().by_hashes(&hashes)
 			.into_iter()
 			.map(|existing_in_pool| existing_in_pool
@@ -378,7 +379,7 @@ impl<B: ChainApi> ValidatedPool<B> {
 	}
 
 	/// Get ready transaction by hash
-	pub fn ready_by_hash(&self, hash: &ExHash<B>) -> Option<TransactionFor<B>> {
+	pub fn ready_by_hash(&self, hash: &ExtrinsicHash<B>) -> Option<TransactionFor<B>> {
 		self.pool.read().ready_by_hash(hash)
 	}
 
@@ -386,7 +387,7 @@ impl<B: ChainApi> ValidatedPool<B> {
 	pub fn prune_tags(
 		&self,
 		tags: impl IntoIterator<Item=Tag>,
-	) -> Result<PruneStatus<ExHash<B>, ExtrinsicFor<B>>, B::Error> {
+	) -> Result<PruneStatus<ExtrinsicHash<B>, ExtrinsicFor<B>>, B::Error> {
 		// Perform tag-based pruning in the base pool
 		let status = self.pool.write().prune_tags(tags);
 		// Notify event listeners of all transactions
@@ -408,8 +409,8 @@ impl<B: ChainApi> ValidatedPool<B> {
 	pub fn resubmit_pruned(
 		&self,
 		at: &BlockId<B::Block>,
-		known_imported_hashes: impl IntoIterator<Item=ExHash<B>> + Clone,
-		pruned_hashes: Vec<ExHash<B>>,
+		known_imported_hashes: impl IntoIterator<Item=ExtrinsicHash<B>> + Clone,
+		pruned_hashes: Vec<ExtrinsicHash<B>>,
 		pruned_xts: Vec<ValidatedTransactionFor<B>>,
 	) -> Result<(), B::Error> {
 		debug_assert_eq!(pruned_hashes.len(), pruned_xts.len());
@@ -440,7 +441,7 @@ impl<B: ChainApi> ValidatedPool<B> {
 	pub fn fire_pruned(
 		&self,
 		at: &BlockId<B::Block>,
-		hashes: impl Iterator<Item=ExHash<B>>,
+		hashes: impl Iterator<Item=ExtrinsicHash<B>>,
 	) -> Result<(), B::Error> {
 		let header_hash = self.api.block_id_to_hash(at)?
 			.ok_or_else(|| error::Error::InvalidBlockId(format!("{:?}", at)).into())?;
@@ -473,7 +474,7 @@ impl<B: ChainApi> ValidatedPool<B> {
 				.map(|tx| tx.hash.clone())
 				.collect::<Vec<_>>()
 		};
-		let futures_to_remove: Vec<ExHash<B>> = {
+		let futures_to_remove: Vec<ExtrinsicHash<B>> = {
 			let p = self.pool.read();
 			let mut hashes = Vec::new();
 			for tx in p.futures() {
@@ -494,7 +495,7 @@ impl<B: ChainApi> ValidatedPool<B> {
 
 	/// Get rotator reference.
 	#[cfg(test)]
-	pub fn rotator(&self) -> &PoolRotator<ExHash<B>> {
+	pub fn rotator(&self) -> &PoolRotator<ExtrinsicHash<B>> {
 		&self.rotator
 	}
 
@@ -507,14 +508,14 @@ impl<B: ChainApi> ValidatedPool<B> {
 	///
 	/// Consumers of this stream should use the `ready` method to actually get the
 	/// pending transactions in the right order.
-	pub fn import_notification_stream(&self) -> EventStream<ExHash<B>> {
+	pub fn import_notification_stream(&self) -> EventStream<ExtrinsicHash<B>> {
 		let (sink, stream) = tracing_unbounded("mpsc_import_notifications");
 		self.import_notification_sinks.lock().push(sink);
 		stream
 	}
 
 	/// Invoked when extrinsics are broadcasted.
-	pub fn on_broadcasted(&self, propagated: HashMap<ExHash<B>, Vec<String>>) {
+	pub fn on_broadcasted(&self, propagated: HashMap<ExtrinsicHash<B>, Vec<String>>) {
 		let mut listener = self.listener.write();
 		for (hash, peers) in propagated.into_iter() {
 			listener.broadcasted(&hash, peers);
@@ -527,7 +528,7 @@ impl<B: ChainApi> ValidatedPool<B> {
 	/// to prevent them from entering the pool right away.
 	/// Note this is not the case for the dependent transactions - those may
 	/// still be valid so we want to be able to re-import them.
-	pub fn remove_invalid(&self, hashes: &[ExHash<B>]) -> Vec<TransactionFor<B>> {
+	pub fn remove_invalid(&self, hashes: &[ExtrinsicHash<B>]) -> Vec<TransactionFor<B>> {
 		// early exit in case there is no invalid transactions.
 		if hashes.is_empty() {
 			return vec![];
diff --git a/client/transaction-pool/src/api.rs b/client/transaction-pool/src/api.rs
index 725fb6ec4a8bf..79315c2724b5b 100644
--- a/client/transaction-pool/src/api.rs
+++ b/client/transaction-pool/src/api.rs
@@ -25,9 +25,7 @@ use futures::{
 };
 
 use sc_client_api::{
-	blockchain::HeaderBackend,
-	light::{Fetcher, RemoteCallRequest, RemoteBodyRequest},
-	BlockBackend,
+	blockchain::HeaderBackend, light::{Fetcher, RemoteCallRequest, RemoteBodyRequest}, BlockBackend,
 };
 use sp_runtime::{
 	generic::BlockId, traits::{self, Block as BlockT, BlockIdTo, Header as HeaderT, Hash as HashT},
@@ -45,10 +43,7 @@ pub struct FullChainApi<Client, Block> {
 	_marker: PhantomData<Block>,
 }
 
-impl<Client, Block> FullChainApi<Client, Block> where
-	Block: BlockT,
-	Client: ProvideRuntimeApi<Block> + BlockIdTo<Block>,
-{
+impl<Client, Block> FullChainApi<Client, Block> {
 	/// Create new transaction pool logic.
 	pub fn new(client: Arc<Client>) -> Self {
 		FullChainApi {
@@ -58,12 +53,13 @@ impl<Client, Block> FullChainApi<Client, Block> where
 				.name_prefix("txpool-verifier")
 				.create()
 				.expect("Failed to spawn verifier threads, that are critical for node operation."),
-			_marker: Default::default()
+			_marker: Default::default(),
 		}
 	}
 }
 
-impl<Client, Block> sc_transaction_graph::ChainApi for FullChainApi<Client, Block> where
+impl<Client, Block> sc_transaction_graph::ChainApi for FullChainApi<Client, Block>
+where
 	Block: BlockT,
 	Client: ProvideRuntimeApi<Block> + BlockBackend<Block> + BlockIdTo<Block>,
 	Client: Send + Sync + 'static,
@@ -71,9 +67,10 @@ impl<Client, Block> sc_transaction_graph::ChainApi for FullChainApi<Client, Bloc
 	sp_api::ApiErrorFor<Client, Block>: Send,
 {
 	type Block = Block;
-	type Hash = Block::Hash;
 	type Error = error::Error;
-	type ValidationFuture = Pin<Box<dyn Future<Output = error::Result<TransactionValidity>> + Send>>;
+	type ValidationFuture = Pin<
+		Box<dyn Future<Output = error::Result<TransactionValidity>> + Send>
+	>;
 	type BodyFuture = Ready<error::Result<Option<Vec<<Self::Block as BlockT>::Extrinsic>>>>;
 
 	fn block_body(&self, id: &BlockId<Self::Block>) -> Self::BodyFuture {
@@ -136,7 +133,10 @@ impl<Client, Block> sc_transaction_graph::ChainApi for FullChainApi<Client, Bloc
 		self.client.to_hash(at).map_err(|e| Error::BlockIdConversion(format!("{:?}", e)))
 	}
 
-	fn hash_and_length(&self, ex: &sc_transaction_graph::ExtrinsicFor<Self>) -> (Self::Hash, usize) {
+	fn hash_and_length(
+		&self,
+		ex: &sc_transaction_graph::ExtrinsicFor<Self>,
+	) -> (sc_transaction_graph::ExtrinsicHash<Self>, usize) {
 		ex.using_encoded(|x| {
 			(<traits::HashFor::<Block> as traits::Hash>::hash(x), x.len())
 		})
@@ -150,11 +150,7 @@ pub struct LightChainApi<Client, F, Block> {
 	_phantom: PhantomData<Block>,
 }
 
-impl<Client, F, Block> LightChainApi<Client, F, Block> where
-	Block: BlockT,
-	Client: HeaderBackend<Block>,
-	F: Fetcher<Block>,
-{
+impl<Client, F, Block> LightChainApi<Client, F, Block> {
 	/// Create new transaction pool logic.
 	pub fn new(client: Arc<Client>, fetcher: Arc<F>) -> Self {
 		LightChainApi {
@@ -165,16 +161,23 @@ impl<Client, F, Block> LightChainApi<Client, F, Block> where
 	}
 }
 
-impl<Client, F, Block> sc_transaction_graph::ChainApi for LightChainApi<Client, F, Block> where
-	Block: BlockT,
-	Client: HeaderBackend<Block> + 'static,
-	F: Fetcher<Block> + 'static,
+impl<Client, F, Block> sc_transaction_graph::ChainApi for
+	LightChainApi<Client, F, Block> where
+		Block: BlockT,
+		Client: HeaderBackend<Block> + 'static,
+		F: Fetcher<Block> + 'static,
 {
 	type Block = Block;
-	type Hash = Block::Hash;
 	type Error = error::Error;
-	type ValidationFuture = Box<dyn Future<Output = error::Result<TransactionValidity>> + Send + Unpin>;
-	type BodyFuture = Pin<Box<dyn Future<Output = error::Result<Option<Vec<<Self::Block as BlockT>::Extrinsic>>>> + Send>>;
+	type ValidationFuture = Box<
+		dyn Future<Output = error::Result<TransactionValidity>> + Send + Unpin
+	>;
+	type BodyFuture = Pin<
+		Box<
+			dyn Future<Output = error::Result<Option<Vec<<Self::Block as BlockT>::Extrinsic>>>>
+				+ Send
+		>
+	>;
 
 	fn validate_transaction(
 		&self,
@@ -211,15 +214,24 @@ impl<Client, F, Block> sc_transaction_graph::ChainApi for LightChainApi<Client,
 		Box::new(remote_validation_request)
 	}
 
-	fn block_id_to_number(&self, at: &BlockId<Self::Block>) -> error::Result<Option<sc_transaction_graph::NumberFor<Self>>> {
+	fn block_id_to_number(
+		&self,
+		at: &BlockId<Self::Block>,
+	) -> error::Result<Option<sc_transaction_graph::NumberFor<Self>>> {
 		Ok(self.client.block_number_from_id(at)?)
 	}
 
-	fn block_id_to_hash(&self, at: &BlockId<Self::Block>) -> error::Result<Option<sc_transaction_graph::BlockHash<Self>>> {
+	fn block_id_to_hash(
+		&self,
+		at: &BlockId<Self::Block>,
+	) -> error::Result<Option<sc_transaction_graph::BlockHash<Self>>> {
 		Ok(self.client.block_hash_from_id(at)?)
 	}
 
-	fn hash_and_length(&self, ex: &sc_transaction_graph::ExtrinsicFor<Self>) -> (Self::Hash, usize) {
+	fn hash_and_length(
+		&self,
+		ex: &sc_transaction_graph::ExtrinsicFor<Self>,
+	) -> (sc_transaction_graph::ExtrinsicHash<Self>, usize) {
 		ex.using_encoded(|x| {
 			(<<Block::Header as HeaderT>::Hashing as HashT>::hash(x), x.len())
 		})
diff --git a/client/transaction-pool/src/lib.rs b/client/transaction-pool/src/lib.rs
index 05d7189a04a0d..326c5e1a751c3 100644
--- a/client/transaction-pool/src/lib.rs
+++ b/client/transaction-pool/src/lib.rs
@@ -35,7 +35,7 @@ pub use sc_transaction_graph as txpool;
 pub use crate::api::{FullChainApi, LightChainApi};
 
 use std::{collections::HashMap, sync::Arc, pin::Pin};
-use futures::{prelude::*, future::ready, channel::oneshot};
+use futures::{prelude::*, future::{ready, self}, channel::oneshot};
 use parking_lot::Mutex;
 
 use sp_runtime::{
@@ -47,14 +47,19 @@ use sp_transaction_pool::{
 	TransactionStatusStreamFor, MaintainedTransactionPool, PoolFuture, ChainEvent,
 	TransactionSource,
 };
+use sc_transaction_graph::ChainApi;
 use wasm_timer::Instant;
 
 use prometheus_endpoint::Registry as PrometheusRegistry;
 use crate::metrics::MetricsLink as PrometheusMetrics;
 
-type BoxedReadyIterator<Hash, Data> = Box<dyn Iterator<Item=Arc<sc_transaction_graph::base_pool::Transaction<Hash, Data>>> + Send>;
+type BoxedReadyIterator<Hash, Data> = Box<
+	dyn Iterator<Item=Arc<sc_transaction_graph::base_pool::Transaction<Hash, Data>>> + Send
+>;
 
-type ReadyIteratorFor<PoolApi> = BoxedReadyIterator<sc_transaction_graph::ExHash<PoolApi>, sc_transaction_graph::ExtrinsicFor<PoolApi>>;
+type ReadyIteratorFor<PoolApi> = BoxedReadyIterator<
+	sc_transaction_graph::ExtrinsicHash<PoolApi>, sc_transaction_graph::ExtrinsicFor<PoolApi>
+>;
 
 type PolledIterator<PoolApi> = Pin<Box<dyn Future<Output=ReadyIteratorFor<PoolApi>> + Send>>;
 
@@ -62,7 +67,7 @@ type PolledIterator<PoolApi> = Pin<Box<dyn Future<Output=ReadyIteratorFor<PoolAp
 pub struct BasicPool<PoolApi, Block>
 	where
 		Block: BlockT,
-		PoolApi: sc_transaction_graph::ChainApi<Block=Block, Hash=Block::Hash>,
+		PoolApi: ChainApi<Block=Block>,
 {
 	pool: Arc<sc_transaction_graph::Pool<PoolApi>>,
 	api: Arc<PoolApi>,
@@ -116,8 +121,7 @@ impl<T, Block: BlockT> ReadyPoll<T, Block> {
 #[cfg(not(target_os = "unknown"))]
 impl<PoolApi, Block> parity_util_mem::MallocSizeOf for BasicPool<PoolApi, Block>
 where
-	PoolApi: sc_transaction_graph::ChainApi<Block=Block, Hash=Block::Hash>,
-	PoolApi::Hash: parity_util_mem::MallocSizeOf,
+	PoolApi: ChainApi<Block=Block>,
 	Block: BlockT,
 {
 	fn size_of(&self, ops: &mut parity_util_mem::MallocSizeOfOps) -> usize {
@@ -146,7 +150,7 @@ pub enum RevalidationType {
 impl<PoolApi, Block> BasicPool<PoolApi, Block>
 	where
 		Block: BlockT,
-		PoolApi: sc_transaction_graph::ChainApi<Block=Block, Hash=Block::Hash> + 'static,
+		PoolApi: ChainApi<Block=Block> + 'static,
 {
 	/// Create new basic transaction pool with provided api.
 	///
@@ -226,11 +230,13 @@ impl<PoolApi, Block> BasicPool<PoolApi, Block>
 impl<PoolApi, Block> TransactionPool for BasicPool<PoolApi, Block>
 	where
 		Block: BlockT,
-		PoolApi: 'static + sc_transaction_graph::ChainApi<Block=Block, Hash=Block::Hash>,
+		PoolApi: 'static + ChainApi<Block=Block>,
 {
 	type Block = PoolApi::Block;
-	type Hash = sc_transaction_graph::ExHash<PoolApi>;
-	type InPoolTransaction = sc_transaction_graph::base_pool::Transaction<TxHash<Self>, TransactionFor<Self>>;
+	type Hash = sc_transaction_graph::ExtrinsicHash<PoolApi>;
+	type InPoolTransaction = sc_transaction_graph::base_pool::Transaction<
+		TxHash<Self>, TransactionFor<Self>
+	>;
 	type Error = PoolApi::Error;
 
 	fn submit_at(
@@ -429,22 +435,51 @@ impl<N: Clone + Copy + AtLeast32Bit> RevalidationStatus<N> {
 	}
 }
 
+/// Prune the known txs for the given block.
+async fn prune_known_txs_for_block<Block: BlockT, Api: ChainApi<Block = Block>>(
+	block_id: BlockId<Block>,
+	api: &Api,
+	pool: &sc_transaction_graph::Pool<Api>,
+) {
+	// We don't query block if we won't prune anything
+	if pool.validated_pool().status().is_empty() {
+		return;
+	}
+
+	let hashes = api.block_body(&block_id).await
+		.unwrap_or_else(|e| {
+			log::warn!("Prune known transactions: error request {:?}!", e);
+			None
+		})
+		.unwrap_or_default()
+		.into_iter()
+		.map(|tx| pool.hash_of(&tx))
+		.collect::<Vec<_>>();
+
+	if let Err(e) = pool.prune_known(&block_id, &hashes) {
+		log::error!("Cannot prune known in the pool {:?}!", e);
+	}
+}
+
 impl<PoolApi, Block> MaintainedTransactionPool for BasicPool<PoolApi, Block>
 	where
 		Block: BlockT,
-		PoolApi: 'static + sc_transaction_graph::ChainApi<Block=Block, Hash=Block::Hash>,
+		PoolApi: 'static + ChainApi<Block=Block>,
 {
 	fn maintain(&self, event: ChainEvent<Self::Block>) -> Pin<Box<dyn Future<Output=()> + Send>> {
 		match event {
-			ChainEvent::NewBlock { id, retracted, .. } => {
-				let id = id.clone();
+			ChainEvent::NewBlock { id, tree_route, is_new_best, .. } => {
 				let pool = self.pool.clone();
 				let api = self.api.clone();
 
 				let block_number = match api.block_id_to_number(&id) {
 					Ok(Some(number)) => number,
 					_ => {
-						log::trace!(target: "txpool", "Skipping chain event - no number for that block {:?}", id);
+						log::trace!(
+							target: "txpool",
+							"Skipping chain event - no number for that block {:?}",
+							id,
+						);
 						return Box::pin(ready(()));
 					}
 				};
@@ -455,40 +490,40 @@ impl<PoolApi, Block> MaintainedTransactionPool for BasicPool<PoolApi, Block>
 					Some(20.into()),
 				);
 				let revalidation_strategy = self.revalidation_strategy.clone();
-				let retracted = retracted.clone();
 				let revalidation_queue = self.revalidation_queue.clone();
 				let ready_poll = self.ready_poll.clone();
 
 				async move {
-					// We don't query block if we won't prune anything
-					if !pool.validated_pool().status().is_empty() {
-						let hashes = api.block_body(&id).await
-							.unwrap_or_else(|e| {
-								log::warn!("Prune known transactions: error request {:?}!", e);
-								None
-							})
-							.unwrap_or_default()
-							.into_iter()
-							.map(|tx| pool.hash_of(&tx))
-							.collect::<Vec<_>>();
-
-						if let Err(e) = pool.prune_known(&id, &hashes) {
-							log::error!("Cannot prune known in the pool {:?}!", e);
-						}
+					// If there is a tree route, we use this to prune known tx based on the enacted
+					// blocks and otherwise we only prune known txs if the block is
+					// the new best block.
+					if let Some(ref tree_route) = tree_route {
+						future::join_all(
+							tree_route
+								.enacted()
+								.iter().map(|h|
+									prune_known_txs_for_block(
+										BlockId::Hash(h.hash.clone()),
+										&*api,
+										&*pool,
+									),
+								),
+						).await;
+					} else if is_new_best {
+						prune_known_txs_for_block(id.clone(), &*api, &*pool).await;
 					}
 
-					let extra_pool = pool.clone();
-					// After #5200 lands, this arguably might be moved to the handler of "all blocks notification".
-					ready_poll.lock().trigger(block_number, move || Box::new(extra_pool.validated_pool().ready()));
-
-					if next_action.resubmit {
+					if let (true, Some(tree_route)) = (next_action.resubmit, tree_route) {
 						let mut resubmit_transactions = Vec::new();
 
-						for retracted_hash in retracted {
+						for retracted in tree_route.retracted() {
+							let hash = retracted.hash.clone();
+
 							// notify txs awaiting finality that it has been retracted
-							pool.validated_pool().on_block_retracted(retracted_hash.clone());
+							pool.validated_pool().on_block_retracted(hash.clone());
 
-							let block_transactions = api.block_body(&BlockId::hash(retracted_hash.clone())).await
+							let block_transactions = api.block_body(&BlockId::hash(hash))
+								.await
 								.unwrap_or_else(|e| {
 									log::warn!("Failed to fetch block body {:?}!", e);
 									None
@@ -499,23 +534,37 @@ impl<PoolApi, Block> MaintainedTransactionPool for BasicPool<PoolApi, Block>
 
 							resubmit_transactions.extend(block_transactions);
 						}
+
 						if let Err(e) = pool.submit_at(
 							&id,
 							// These transactions are coming from retracted blocks, we should
 							// simply consider them external.
 							TransactionSource::External,
 							resubmit_transactions,
-							true
+							true,
 						).await {
 							log::debug!(
 								target: "txpool",
-								"[{:?}] Error re-submitting transactions: {:?}", id, e
+								"[{:?}] Error re-submitting transactions: {:?}",
+								id,
+								e,
 							)
 						}
 					}
 
+					let extra_pool = pool.clone();
+					// After #5200 lands, this arguably might be moved to the
+					// handler of "all blocks notification".
+					ready_poll.lock().trigger(
+						block_number,
+						move || Box::new(extra_pool.validated_pool().ready()),
+					);
+
 					if next_action.revalidate {
-						let hashes = pool.validated_pool().ready().map(|tx| tx.hash.clone()).collect();
+						let hashes = pool.validated_pool()
+							.ready()
+							.map(|tx| tx.hash.clone())
+							.collect();
 						revalidation_queue.revalidate_later(block_number, hashes).await;
 					}
 
diff --git a/client/transaction-pool/src/revalidation.rs b/client/transaction-pool/src/revalidation.rs
index 423ff92ba4db0..05a2076c6659e 100644
--- a/client/transaction-pool/src/revalidation.rs
+++ b/client/transaction-pool/src/revalidation.rs
@@ -20,7 +20,7 @@
 
 use std::{sync::Arc, pin::Pin, collections::{HashMap, HashSet, BTreeMap}};
 
-use sc_transaction_graph::{ChainApi, Pool, ExHash, NumberFor, ValidatedTransaction};
+use sc_transaction_graph::{ChainApi, Pool, ExtrinsicHash, NumberFor, ValidatedTransaction};
 use sp_runtime::traits::{Zero, SaturatedConversion};
 use sp_runtime::generic::BlockId;
 use sp_runtime::transaction_validity::TransactionValidityError;
@@ -39,7 +39,7 @@ const BACKGROUND_REVALIDATION_BATCH_SIZE: usize = 20;
 /// Payload from queue to worker.
 struct WorkerPayload<Api: ChainApi> {
 	at: NumberFor<Api>,
-	transactions: Vec<ExHash<Api>>,
+	transactions: Vec<ExtrinsicHash<Api>>,
 }
 
 /// Async revalidation worker.
@@ -49,8 +49,8 @@ struct RevalidationWorker<Api: ChainApi> {
 	api: Arc<Api>,
 	pool: Arc<Pool<Api>>,
 	best_block: NumberFor<Api>,
-	block_ordered: BTreeMap<NumberFor<Api>, HashSet<ExHash<Api>>>,
-	members: HashMap<ExHash<Api>, NumberFor<Api>>,
+	block_ordered: BTreeMap<NumberFor<Api>, HashSet<ExtrinsicHash<Api>>>,
+	members: HashMap<ExtrinsicHash<Api>, NumberFor<Api>>,
 }
 
 impl<Api: ChainApi> Unpin for RevalidationWorker<Api> {}
@@ -63,7 +63,7 @@ async fn batch_revalidate<Api: ChainApi>(
 	pool: Arc<Pool<Api>>,
 	api: Arc<Api>,
 	at: NumberFor<Api>,
-	batch: impl IntoIterator<Item=ExHash<Api>>,
+	batch: impl IntoIterator<Item=ExtrinsicHash<Api>>,
 ) {
 	let mut invalid_hashes = Vec::new();
 	let mut revalidated = HashMap::new();
@@ -129,7 +129,7 @@ impl<Api: ChainApi> RevalidationWorker<Api> {
 		}
 	}
 
-	fn prepare_batch(&mut self) -> Vec<ExHash<Api>> {
+	fn prepare_batch(&mut self) -> Vec<ExtrinsicHash<Api>> {
 		let mut queued_exts = Vec::new();
 		let mut left = BACKGROUND_REVALIDATION_BATCH_SIZE;
 
@@ -334,7 +334,7 @@ where
 	/// If queue configured with background worker, this will return immediately.
 	/// If queue configured without background worker, this will resolve after
 	/// revalidation is actually done.
-	pub async fn revalidate_later(&self, at: NumberFor<Api>, transactions: Vec<ExHash<Api>>) {
+	pub async fn revalidate_later(&self, at: NumberFor<Api>, transactions: Vec<ExtrinsicHash<Api>>) {
 		if transactions.len() > 0 {
 			log::debug!(target: "txpool", "Sent {} transactions to revalidation queue", transactions.len());
 		}
@@ -359,9 +359,7 @@ mod tests {
 	use sp_transaction_pool::TransactionSource;
 	use substrate_test_runtime_transaction_pool::{TestApi, uxt};
 	use futures::executor::block_on;
-	use substrate_test_runtime_client::{
-		AccountKeyring::*,
-	};
+	use substrate_test_runtime_client::AccountKeyring::*;
 
 	fn setup() -> (Arc<TestApi>, Pool<TestApi>) {
 		let test_api = Arc::new(TestApi::empty());
diff --git a/client/transaction-pool/src/testing/pool.rs b/client/transaction-pool/src/testing/pool.rs
index 4f30d5b6c3500..dafd829c64d11 100644
--- a/client/transaction-pool/src/testing/pool.rs
+++ b/client/transaction-pool/src/testing/pool.rs
@@ -25,12 +25,12 @@ use sp_runtime::{
 	transaction_validity::{ValidTransaction, TransactionSource, InvalidTransaction},
 };
 use substrate_test_runtime_client::{
-	runtime::{Block, Hash, Index, Header, Extrinsic, Transfer},
-	AccountKeyring::*,
+	runtime::{Block, Hash, Index, Header, Extrinsic, Transfer}, AccountKeyring::*,
 };
 use substrate_test_runtime_transaction_pool::{TestApi, uxt};
 use futures::{prelude::*, task::Poll};
 use codec::Encode;
+use std::collections::BTreeSet;
 
 fn pool() -> Pool<TestApi> {
 	Pool::new(Default::default(), TestApi::with_alice_nonce(209).into())
@@ -42,7 +42,7 @@ fn maintained_pool() -> (
 	intervalier::BackSignalControl,
 ) {
 	let (pool, background_task, notifier) = BasicPool::new_test(
-		std::sync::Arc::new(TestApi::with_alice_nonce(209))
+		Arc::new(TestApi::with_alice_nonce(209)),
 	);
 
 	let thread_pool = futures::executor::ThreadPool::new().unwrap();
@@ -112,6 +112,7 @@ fn prune_tags_should_work() {
 	let pending: Vec<_> = pool.validated_pool().ready().map(|a| a.data.transfer().nonce).collect();
 	assert_eq!(pending, vec![209, 210]);
 
+	pool.validated_pool().api().push_block(1, Vec::new());
 	block_on(
 		pool.prune_tags(
 			&BlockId::number(1),
@@ -140,6 +141,37 @@ fn should_ban_invalid_transactions() {
 	block_on(pool.submit_one(&BlockId::number(0), SOURCE, uxt.clone())).unwrap_err();
 }
 
+#[test]
+fn only_prune_on_new_best() {
+	let pool = maintained_pool().0;
+	let uxt = uxt(Alice, 209);
+
+	let _ = block_on(
+		pool.submit_and_watch(&BlockId::number(1), SOURCE, uxt.clone())
+	).expect("1. Imported");
+	let header = pool.api.push_block(1, vec![uxt.clone()]);
+	assert_eq!(pool.status().ready, 1);
+
+	let event = ChainEvent::NewBlock {
+		id: BlockId::Number(1),
+		is_new_best: false,
+		header: header.clone(),
+		tree_route: None,
+	};
+	block_on(pool.maintain(event));
+	assert_eq!(pool.status().ready, 1);
+
+	let header = pool.api.push_block(2, vec![uxt]);
+	let event = ChainEvent::NewBlock {
+		id: BlockId::Number(2),
+		is_new_best: true,
+		header: header.clone(),
+		tree_route: None,
+	};
+	block_on(pool.maintain(event));
+	assert_eq!(pool.status().ready, 0);
+}
+
 #[test]
 fn should_correctly_prune_transactions_providing_more_than_one_tag() {
 	let api = Arc::new(TestApi::with_alice_nonce(209));
@@ -153,6 +185,7 @@ fn should_correctly_prune_transactions_providing_more_than_one_tag() {
 
 	// remove the transaction that just got imported.
 	api.increment_nonce(Alice.into());
+	api.push_block(1, Vec::new());
 	block_on(pool.prune_tags(&BlockId::number(1), vec![vec![209]], vec![])).expect("1. Pruned");
 	assert_eq!(pool.validated_pool().status().ready, 0);
 	// it's re-imported to future
@@ -160,6 +193,7 @@ fn should_correctly_prune_transactions_providing_more_than_one_tag() {
 
 	// so now let's insert another transaction that also provides the 155
 	api.increment_nonce(Alice.into());
+	api.push_block(2, Vec::new());
 	let xt = uxt(Alice, 211);
 	block_on(pool.submit_one(&BlockId::number(2), SOURCE, xt.clone())).expect("2. Imported");
 	assert_eq!(pool.validated_pool().status().ready, 1);
@@ -169,6 +203,7 @@ fn should_correctly_prune_transactions_providing_more_than_one_tag() {
 
 	// prune it and make sure the pool is empty
 	api.increment_nonce(Alice.into());
+	api.push_block(3, Vec::new());
 	block_on(pool.prune_tags(&BlockId::number(3), vec![vec![155]], vec![])).expect("2. Pruned");
 	assert_eq!(pool.validated_pool().status().ready, 0);
 	assert_eq!(pool.validated_pool().status().future, 2);
@@ -178,21 +213,26 @@ fn block_event(id: u64) -> ChainEvent<Block> {
 	ChainEvent::NewBlock {
 		id: BlockId::number(id),
 		is_new_best: true,
-		retracted: vec![],
+		tree_route: None,
 		header: header(id),
 	}
 }
 
-fn block_event_with_retracted(id: u64, retracted: Vec<Hash>) -> ChainEvent<Block> {
+fn block_event_with_retracted(
+	header: Header,
+	retracted_start: Hash,
+	api: &TestApi,
+) -> ChainEvent<Block> {
+	let tree_route = api.tree_route(retracted_start, header.hash()).expect("Tree route exists");
+
 	ChainEvent::NewBlock {
-		id: BlockId::number(id),
+		id: BlockId::hash(header.hash()),
 		is_new_best: true,
-		retracted: retracted,
-		header: header(id),
+		tree_route: Some(Arc::new(tree_route)),
+		header,
 	}
 }
 
-
 #[test]
 fn should_prune_old_during_maintenance() {
 	let xt = uxt(Alice, 209);
@@ -232,17 +272,16 @@ fn should_revalidate_during_maintenance() {
 #[test]
 fn should_resubmit_from_retracted_during_maintenance() {
 	let xt = uxt(Alice, 209);
-	let retracted_hash = Hash::random();
 
 	let (pool, _guard, _notifier) = maintained_pool();
 
 	block_on(pool.submit_one(&BlockId::number(0), SOURCE, xt.clone())).expect("1. Imported");
 	assert_eq!(pool.status().ready, 1);
 
-	pool.api.push_block(1, vec![]);
-	pool.api.push_fork_block(retracted_hash, vec![xt.clone()]);
+	let header = pool.api.push_block(1, vec![]);
+	let fork_header = pool.api.push_block(1, vec![]);
 
-	let event = block_event_with_retracted(1, vec![retracted_hash]);
+	let event = block_event_with_retracted(header, fork_header.hash(), &*pool.api);
 
 	block_on(pool.maintain(event));
 	assert_eq!(pool.status().ready, 1);
@@ -251,18 +290,17 @@ fn should_resubmit_from_retracted_during_maintenance() {
 #[test]
 fn should_not_retain_invalid_hashes_from_retracted() {
 	let xt = uxt(Alice, 209);
-	let retracted_hash = Hash::random();
 
 	let (pool, _guard, mut notifier) = maintained_pool();
 
 	block_on(pool.submit_one(&BlockId::number(0), SOURCE, xt.clone())).expect("1. Imported");
 	assert_eq!(pool.status().ready, 1);
 
-	pool.api.push_block(1, vec![]);
-	pool.api.push_fork_block(retracted_hash, vec![xt.clone()]);
+	let header = pool.api.push_block(1, vec![]);
+	let fork_header = pool.api.push_block(1, vec![xt.clone()]);
 	pool.api.add_invalid(&xt);
 
-	let event = block_event_with_retracted(1, vec![retracted_hash]);
+	let event = block_event_with_retracted(header, fork_header.hash(), &*pool.api);
 
 	block_on(pool.maintain(event));
 	block_on(notifier.next());
@@ -389,15 +427,24 @@ fn should_push_watchers_during_maintaince() {
 	// events for hash2 are: Ready, InBlock
 	assert_eq!(
 		futures::executor::block_on_stream(watcher0).collect::<Vec<_>>(),
-		vec![TransactionStatus::Ready, TransactionStatus::InBlock(header_hash.clone()), TransactionStatus::Finalized(header_hash.clone())],
+		vec![
+			TransactionStatus::Ready,
+			TransactionStatus::InBlock(header_hash.clone()),
+			TransactionStatus::Finalized(header_hash.clone())],
 	);
 	assert_eq!(
 		futures::executor::block_on_stream(watcher1).collect::<Vec<_>>(),
-		vec![TransactionStatus::Ready, TransactionStatus::InBlock(header_hash.clone()), TransactionStatus::Finalized(header_hash.clone())],
+		vec![
+			TransactionStatus::Ready,
+			TransactionStatus::InBlock(header_hash.clone()),
+			TransactionStatus::Finalized(header_hash.clone())],
 	);
 	assert_eq!(
 		futures::executor::block_on_stream(watcher2).collect::<Vec<_>>(),
-		vec![TransactionStatus::Ready, TransactionStatus::InBlock(header_hash.clone()), TransactionStatus::Finalized(header_hash.clone())],
+		vec![
+			TransactionStatus::Ready,
+			TransactionStatus::InBlock(header_hash.clone()),
+			TransactionStatus::Finalized(header_hash.clone())],
 	);
 }
 
@@ -423,12 +470,12 @@ fn finalization() {
 	).expect("1. Imported");
 	pool.api.push_block(2, vec![xt.clone()]);
 
-	let header = pool.api.chain().read().header_by_number.get(&2).cloned().unwrap();
+	let header = pool.api.chain().read().block_by_number.get(&2).unwrap()[0].header().clone();
 	let event = ChainEvent::NewBlock {
 		id: BlockId::Hash(header.hash()),
 		is_new_best: true,
 		header: header.clone(),
-		retracted: vec![]
+		tree_route: None,
 	};
 	block_on(pool.maintain(event));
 
@@ -467,7 +514,6 @@ fn fork_aware_finalization() {
 	let c2;
 	let d2;
 
-
 	// block B1
 	{
 		let watcher = block_on(
@@ -481,7 +527,7 @@ fn fork_aware_finalization() {
 			id: BlockId::Number(2),
 			is_new_best: true,
 			header: header.clone(),
-			retracted: vec![],
+			tree_route: None,
 		};
 		b1 = header.hash();
 		block_on(pool.maintain(event));
@@ -492,7 +538,7 @@ fn fork_aware_finalization() {
 
 	// block C2
 	{
-		let header = pool.api.push_fork_block_with_parent(b1, vec![from_dave.clone()]);
+		let header = pool.api.push_block_with_parent(b1, vec![from_dave.clone()]);
 		from_dave_watcher = block_on(
 			pool.submit_and_watch(&BlockId::number(1), SOURCE, from_dave.clone())
 		).expect("1. Imported");
@@ -501,7 +547,7 @@ fn fork_aware_finalization() {
 			id: BlockId::Hash(header.hash()),
 			is_new_best: true,
 			header: header.clone(),
-			retracted: vec![]
+			tree_route: None,
 		};
 		c2 = header.hash();
 		block_on(pool.maintain(event));
@@ -514,13 +560,13 @@ fn fork_aware_finalization() {
 			pool.submit_and_watch(&BlockId::number(1), SOURCE, from_bob.clone())
 		).expect("1. Imported");
 		assert_eq!(pool.status().ready, 1);
-		let header = pool.api.push_fork_block_with_parent(c2, vec![from_bob.clone()]);
+		let header = pool.api.push_block_with_parent(c2, vec![from_bob.clone()]);
 
 		let event = ChainEvent::NewBlock {
 			id: BlockId::Hash(header.hash()),
 			is_new_best: true,
 			header: header.clone(),
-			retracted: vec![]
+			tree_route: None,
 		};
 		d2 = header.hash();
 		block_on(pool.maintain(event));
@@ -536,14 +582,10 @@ fn fork_aware_finalization() {
 		let header = pool.api.push_block(3, vec![from_charlie.clone()]);
 
 		canon_watchers.push((watcher, header.hash()));
-		let event = ChainEvent::NewBlock {
-			id: BlockId::Number(3),
-			is_new_best: true,
-			header: header.clone(),
-			retracted: vec![c2, d2],
-		};
+		let event = block_event_with_retracted(header.clone(), d2, &*pool.api);
 		block_on(pool.maintain(event));
 		assert_eq!(pool.status().ready, 2);
+
 		let event = ChainEvent::Finalized { hash: header.hash() };
 		block_on(pool.maintain(event));
 	}
@@ -562,7 +604,7 @@ fn fork_aware_finalization() {
 			id: BlockId::Hash(header.hash()),
 			is_new_best: true,
 			header: header.clone(),
-			retracted: vec![]
+			tree_route: None,
 		};
 		d1 = header.hash();
 		block_on(pool.maintain(event));
@@ -581,7 +623,7 @@ fn fork_aware_finalization() {
 			id: BlockId::Hash(header.hash()),
 			is_new_best: true,
 			header: header.clone(),
-			retracted: vec![]
+			tree_route: None,
 		};
 		block_on(pool.maintain(event));
 		assert_eq!(pool.status().ready, 0);
@@ -599,7 +641,7 @@ fn fork_aware_finalization() {
 
 
 	{
-		let mut stream= futures::executor::block_on_stream(from_dave_watcher);
+		let mut stream = futures::executor::block_on_stream(from_dave_watcher);
 		assert_eq!(stream.next(), Some(TransactionStatus::Ready));
 		assert_eq!(stream.next(), Some(TransactionStatus::InBlock(c2.clone())));
 		assert_eq!(stream.next(), Some(TransactionStatus::Retracted(c2)));
@@ -610,7 +652,7 @@ fn fork_aware_finalization() {
 	}
 
 	{
-		let mut stream= futures::executor::block_on_stream(from_bob_watcher);
+		let mut stream = futures::executor::block_on_stream(from_bob_watcher);
 		assert_eq!(stream.next(), Some(TransactionStatus::Ready));
 		assert_eq!(stream.next(), Some(TransactionStatus::InBlock(d2.clone())));
 		assert_eq!(stream.next(), Some(TransactionStatus::Retracted(d2)));
@@ -621,6 +663,217 @@ fn fork_aware_finalization() {
 	}
 }
 
+/// This test ensures that transactions from a fork are re-submitted if
+/// the forked block is not part of the retracted blocks. This happens as the
+/// retracted block list only contains the route from the old best to the new
+/// best, without any further forks.
+///
+/// Given the following:
+///
+///     -> D0 (old best, tx0)
+///    /
+/// C - -> D1 (tx1)
+///    \
+///     -> D2 (new best)
+///
+/// Retracted will contain `D0`, but we need to re-submit `tx0` and `tx1` as both
+/// blocks are not part of the canonical chain.
+#[test]
+fn resubmit_tx_of_fork_that_is_not_part_of_retracted() {
+	let api = TestApi::empty();
+	// starting block A1 (last finalized.)
+	api.push_block(1, vec![]);
+
+	let (pool, _background, _) = BasicPool::new_test(api.into());
+
+	let tx0 = uxt(Alice, 1);
+	let tx1 = uxt(Dave, 2);
+	pool.api.increment_nonce(Alice.into());
+	pool.api.increment_nonce(Dave.into());
+
+	let d0;
+
+	// Block D0
+	{
+		let _ = block_on(
+			pool.submit_and_watch(&BlockId::number(1), SOURCE, tx0.clone())
+		).expect("1. Imported");
+		let header = pool.api.push_block(2, vec![tx0.clone()]);
+		assert_eq!(pool.status().ready, 1);
+
+		let event = ChainEvent::NewBlock {
+			id: BlockId::Number(2),
+			is_new_best: true,
+			header: header.clone(),
+			tree_route: None,
+		};
+		d0 = header.hash();
+		block_on(pool.maintain(event));
+		assert_eq!(pool.status().ready, 0);
+	}
+
+	// Block D1
+	{
+		let _ = block_on(
+			pool.submit_and_watch(&BlockId::number(1), SOURCE, tx1.clone())
+		).expect("1. Imported");
+		let header = pool.api.push_block(2, vec![tx1.clone()]);
+		assert_eq!(pool.status().ready, 1);
+		let event = ChainEvent::NewBlock {
+			id: BlockId::Hash(header.hash()),
+			is_new_best: false,
+			header: header.clone(),
+			tree_route: None,
+		};
+		block_on(pool.maintain(event));
+
+		// Only transactions from new best should be pruned
+		assert_eq!(pool.status().ready, 1);
+	}
+
+	// Block D2
+	{
+		let header = pool.api.push_block(2, vec![]);
+		let event = block_event_with_retracted(header, d0, &*pool.api);
+		block_on(pool.maintain(event));
+		assert_eq!(pool.status().ready, 2);
+	}
+}
+
+#[test]
+fn resubmit_from_retracted_fork() {
+	let api = TestApi::empty();
+	// starting block A1 (last finalized.)
+	api.push_block(1, vec![]);
+
+	let (pool, _background, _) = BasicPool::new_test(api.into());
+
+	let tx0 = uxt(Alice, 1);
+	let tx1 = uxt(Dave, 2);
+	let tx2 = uxt(Bob, 3);
+
+	// Transactions of the fork that will be enacted later
+	let tx3 = uxt(Eve, 1);
+	let tx4 = uxt(Ferdie, 2);
+	let tx5 = uxt(One, 3);
+
+	pool.api.increment_nonce(Alice.into());
+	pool.api.increment_nonce(Dave.into());
+	pool.api.increment_nonce(Bob.into());
+	pool.api.increment_nonce(Eve.into());
+	pool.api.increment_nonce(Ferdie.into());
+	pool.api.increment_nonce(One.into());
+
+	// Block D0
+	{
+		let _ = block_on(
+			pool.submit_and_watch(&BlockId::number(1), SOURCE, tx0.clone())
+		).expect("1. Imported");
+		let header = pool.api.push_block(2, vec![tx0.clone()]);
+		assert_eq!(pool.status().ready, 1);
+
+		let event = ChainEvent::NewBlock {
+			id: BlockId::Number(2),
+			is_new_best: true,
+			header: header.clone(),
+			tree_route: None,
+		};
+		block_on(pool.maintain(event));
+		assert_eq!(pool.status().ready, 0);
+	}
+
+	// Block E0
+	{
+		let _ = block_on(
+			pool.submit_and_watch(&BlockId::number(1), SOURCE, tx1.clone())
+		).expect("1. Imported");
+		let header = pool.api.push_block(3, vec![tx1.clone()]);
+		let event = ChainEvent::NewBlock {
+			id: BlockId::Hash(header.hash()),
+			is_new_best: true,
+			header: header.clone(),
+			tree_route: None,
+		};
+		block_on(pool.maintain(event));
+		assert_eq!(pool.status().ready, 0);
+	}
+
+	// Block F0
+	let f0 = {
+		let _ = block_on(
+			pool.submit_and_watch(&BlockId::number(1), SOURCE, tx2.clone())
+		).expect("1. Imported");
+		let header = pool.api.push_block(4, vec![tx2.clone()]);
+		let event = ChainEvent::NewBlock {
+			id: BlockId::Hash(header.hash()),
+			is_new_best: true,
+			header: header.clone(),
+			tree_route: None,
+		};
+		block_on(pool.maintain(event));
+		assert_eq!(pool.status().ready, 0);
+		header.hash()
+	};
+
+	// Block D1
+	let d1 = {
+		let _ = block_on(
+			pool.submit_and_watch(&BlockId::number(1), SOURCE, tx3.clone())
+		).expect("1. Imported");
+		let header = pool.api.push_block(2, vec![tx3.clone()]);
+		let event = ChainEvent::NewBlock {
+			id: BlockId::Hash(header.hash()),
+			is_new_best: false,
+			header: header.clone(),
+			tree_route: None,
+		};
+		block_on(pool.maintain(event));
+		assert_eq!(pool.status().ready, 1);
+		header.hash()
+	};
+
+	// Block E1
+	let e1 = {
+		let _ = block_on(
+			pool.submit_and_watch(&BlockId::number(1), SOURCE, tx4.clone())
+		).expect("1. Imported");
+		let header = pool.api.push_block_with_parent(d1.clone(), vec![tx4.clone()]);
+		let event = ChainEvent::NewBlock {
+			id: BlockId::Hash(header.hash()),
+			is_new_best: false,
+			header: header.clone(),
+			tree_route: None,
+		};
+		block_on(pool.maintain(event));
+		assert_eq!(pool.status().ready, 2);
+		header.hash()
+	};
+
+	// Block F1
+	let f1_header = {
+		let _ = block_on(
+			pool.submit_and_watch(&BlockId::number(1), SOURCE, tx5.clone())
+		).expect("1. Imported");
+		let header = pool.api.push_block_with_parent(e1.clone(), vec![tx5.clone()]);
+		// Don't announce the block event to the pool directly, because we will
+		// re-org to this block.
+		assert_eq!(pool.status().ready, 3);
+		header
+	};
+
+	let ready = pool.ready().map(|t| t.data.encode()).collect::<BTreeSet<_>>();
+	let expected_ready = vec![tx3, tx4, tx5].iter().map(Encode::encode).collect::<BTreeSet<_>>();
+	assert_eq!(expected_ready, ready);
+
+	let event = block_event_with_retracted(f1_header, f0, &*pool.api);
+	block_on(pool.maintain(event));
+
+	assert_eq!(pool.status().ready, 3);
+	let ready = pool.ready().map(|t| t.data.encode()).collect::<BTreeSet<_>>();
+	let expected_ready = vec![tx0, tx1, tx2].iter().map(Encode::encode).collect::<BTreeSet<_>>();
+	assert_eq!(expected_ready, ready);
+}
+
 #[test]
 fn ready_set_should_not_resolve_before_block_update() {
 	let (pool, _guard, _notifier) = maintained_pool();
@@ -678,6 +931,7 @@ fn should_not_accept_old_signatures() {
 	use std::convert::TryFrom;
 
 	let client = Arc::new(substrate_test_runtime_client::new());
+
 	let pool = Arc::new(
 		BasicPool::new_test(Arc::new(FullChainApi::new(client))).0
 	);
diff --git a/primitives/blockchain/Cargo.toml b/primitives/blockchain/Cargo.toml
index d76d9c72091c0..689d84d80fcf0 100644
--- a/primitives/blockchain/Cargo.toml
+++ b/primitives/blockchain/Cargo.toml
@@ -12,7 +12,6 @@ documentation = "https://docs.rs/sp-blockchain"
 [package.metadata.docs.rs]
 targets = ["x86_64-unknown-linux-gnu"]
 
-
 [dependencies]
 log = "0.4.8"
 lru = "0.4.0"
diff --git a/primitives/blockchain/src/header_metadata.rs b/primitives/blockchain/src/header_metadata.rs
index a4df04b507fd1..b8d9c5c934581 100644
--- a/primitives/blockchain/src/header_metadata.rs
+++ b/primitives/blockchain/src/header_metadata.rs
@@ -137,7 +137,8 @@ pub fn tree_route<Block: BlockT, T: HeaderMetadata<Block>>(
 		from = backend.header_metadata(from.parent)?;
 	}
 
-	// add the pivot block. and append the reversed to-branch (note that it's reverse order originals)
+	// add the pivot block. and append the reversed to-branch
+	// (note that it's reverse order originals)
 	let pivot = from_branch.len();
 	from_branch.push(HashAndNumber {
 		number: to.number,
@@ -182,18 +183,24 @@ pub struct HashAndNumber<Block: BlockT> {
 /// Tree route from C to E2. Retracted empty. Common is C, enacted [E1, E2]
 /// C -> E1 -> E2
 /// ```
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct TreeRoute<Block: BlockT> {
 	route: Vec<HashAndNumber<Block>>,
 	pivot: usize,
 }
 
 impl<Block: BlockT> TreeRoute<Block> {
-	/// Get a slice of all retracted blocks in reverse order (towards common ancestor)
+	/// Get a slice of all retracted blocks in reverse order (towards common ancestor).
 	pub fn retracted(&self) -> &[HashAndNumber<Block>] {
 		&self.route[..self.pivot]
 	}
 
+	/// Convert into all retracted blocks in reverse order (towards common ancestor).
+	pub fn into_retracted(mut self) -> Vec<HashAndNumber<Block>> {
+		self.route.truncate(self.pivot);
+		self.route
+	}
+
 	/// Get the common ancestor block. This might be one of the two blocks of the
 	/// route.
 	pub fn common_block(&self) -> &HashAndNumber<Block> {
@@ -213,8 +220,15 @@ pub trait HeaderMetadata<Block: BlockT> {
 	/// Error used in case the header metadata is not found.
 	type Error;
 
-	fn header_metadata(&self, hash: Block::Hash) -> Result<CachedHeaderMetadata<Block>, Self::Error>;
-	fn insert_header_metadata(&self, hash: Block::Hash, header_metadata: CachedHeaderMetadata<Block>);
+	fn header_metadata(
+		&self,
+		hash: Block::Hash,
+	) -> Result<CachedHeaderMetadata<Block>, Self::Error>;
+	fn insert_header_metadata(
+		&self,
+		hash: Block::Hash,
+		header_metadata: CachedHeaderMetadata<Block>,
+	);
 	fn remove_header_metadata(&self, hash: Block::Hash);
 }
 
diff --git a/primitives/transaction-pool/Cargo.toml b/primitives/transaction-pool/Cargo.toml
index dbb21f34b6e0c..b7673e8da0d5c 100644
--- a/primitives/transaction-pool/Cargo.toml
+++ b/primitives/transaction-pool/Cargo.toml
@@ -20,6 +20,7 @@ futures = { version = "0.3.1", optional = true }
 log = { version = "0.4.8", optional = true }
 serde = { version = "1.0.101", features = ["derive"], optional = true}
 sp-api = { version = "2.0.0-rc2", default-features = false, path = "../api" }
+sp-blockchain = { version = "2.0.0-rc2", optional = true, path = "../blockchain" }
 sp-runtime = { version = "2.0.0-rc2", default-features = false, path = "../runtime" }
 sp-utils = { version = "2.0.0-rc2", default-features = false, path = "../utils" }
 
@@ -32,5 +33,6 @@ std = [
 	"log",
 	"serde",
 	"sp-api/std",
+	"sp-blockchain",
 	"sp-runtime/std",
 ]
diff --git a/primitives/transaction-pool/src/pool.rs b/primitives/transaction-pool/src/pool.rs
index 762ff06a9eebb..fa50ef9e41775 100644
--- a/primitives/transaction-pool/src/pool.rs
+++ b/primitives/transaction-pool/src/pool.rs
@@ -255,8 +255,10 @@ pub enum ChainEvent<B: BlockT> {
 		id: BlockId<B>,
 		/// Header of the just imported block
 		header: B::Header,
-		/// List of retracted blocks ordered by block number.
-		retracted: Vec<B::Hash>,
+		/// Tree route from old best to new best that was calculated on import.
+		///
+		/// If `None`, no re-org happened on import.
+		tree_route: Option<Arc<sp_blockchain::TreeRoute<B>>>,
 	},
 	/// An existing block has been finalized.
 	Finalized {
diff --git a/test-utils/runtime/client/src/lib.rs b/test-utils/runtime/client/src/lib.rs
index 5b0eafb4a3d64..f2e049bc0f56b 100644
--- a/test-utils/runtime/client/src/lib.rs
+++ b/test-utils/runtime/client/src/lib.rs
@@ -35,12 +35,9 @@ use sp_core::{sr25519, ChangesTrieConfiguration};
 use sp_core::storage::{ChildInfo, Storage, StorageChild};
 use substrate_test_runtime::genesismap::{GenesisConfig, additional_storage_with_genesis};
 use sp_runtime::traits::{Block as BlockT, Header as HeaderT, Hash as HashT, NumberFor, HashFor};
-use sc_service::client::{
-	light::fetcher::{
-		Fetcher,
-		RemoteHeaderRequest, RemoteReadRequest, RemoteReadChildRequest,
-		RemoteCallRequest, RemoteChangesRequest, RemoteBodyRequest,
-	},
+use sc_service::client::light::fetcher::{
+	Fetcher, RemoteHeaderRequest, RemoteReadRequest, RemoteReadChildRequest,
+	RemoteCallRequest, RemoteChangesRequest, RemoteBodyRequest,
 };
 
 /// A prelude to import in tests.
diff --git a/test-utils/runtime/src/lib.rs b/test-utils/runtime/src/lib.rs
index eaceef2defb49..bf6c7450c5086 100644
--- a/test-utils/runtime/src/lib.rs
+++ b/test-utils/runtime/src/lib.rs
@@ -208,6 +208,8 @@ pub type AccountSignature = sr25519::Signature;
 pub type AccountId = <AccountSignature as Verify>::Signer;
 /// A simple hash type for all our hashing.
 pub type Hash = H256;
+/// The hashing algorithm used.
+pub type Hashing = BlakeTwo256;
 /// The block number type used in this runtime.
 pub type BlockNumber = u64;
 /// Index of a transaction.
@@ -219,7 +221,7 @@ pub type Digest = sp_runtime::generic::Digest<H256>;
 /// A test block.
 pub type Block = sp_runtime::generic::Block<Header, Extrinsic>;
 /// A test block's header.
-pub type Header = sp_runtime::generic::Header<BlockNumber, BlakeTwo256>;
+pub type Header = sp_runtime::generic::Header<BlockNumber, Hashing>;
 
 /// Run whatever tests we have.
 pub fn run_tests(mut input: &[u8]) -> Vec<u8> {
@@ -404,7 +406,7 @@ impl frame_system::Trait for Runtime {
 	type Index = u64;
 	type BlockNumber = u64;
 	type Hash = H256;
-	type Hashing = BlakeTwo256;
+	type Hashing = Hashing;
 	type AccountId = u64;
 	type Lookup = IdentityLookup<Self::AccountId>;
 	type Header = Header;
@@ -466,7 +468,7 @@ fn code_using_trie() -> u64 {
 	let mut root = sp_std::default::Default::default();
 	let _ = {
 		let v = &pairs;
-		let mut t = TrieDBMut::<BlakeTwo256>::new(&mut mdb, &mut root);
+		let mut t = TrieDBMut::<Hashing>::new(&mut mdb, &mut root);
 		for i in 0..v.len() {
 			let key: &[u8]= &v[i].0;
 			let val: &[u8] = &v[i].1;
@@ -477,7 +479,7 @@ fn code_using_trie() -> u64 {
 		t
 	};
 
-	if let Ok(trie) = TrieDB::<BlakeTwo256>::new(&mdb, &root) {
+	if let Ok(trie) = TrieDB::<Hashing>::new(&mdb, &root) {
 		if let Ok(iter) = trie.iter() {
 			let mut iter_pairs = Vec::new();
 			for pair in iter {
diff --git a/test-utils/runtime/transaction-pool/src/lib.rs b/test-utils/runtime/transaction-pool/src/lib.rs
index c7778a51da105..5140cb8b9258f 100644
--- a/test-utils/runtime/transaction-pool/src/lib.rs
+++ b/test-utils/runtime/transaction-pool/src/lib.rs
@@ -23,17 +23,18 @@ use codec::Encode;
 use parking_lot::RwLock;
 use sp_runtime::{
 	generic::{self, BlockId},
-	traits::{BlakeTwo256, Hash as HashT},
+	traits::{BlakeTwo256, Hash as HashT, Block as _, Header as _},
 	transaction_validity::{
 		TransactionValidity, ValidTransaction, TransactionValidityError, InvalidTransaction,
 		TransactionSource,
 	},
 };
-use std::collections::{HashSet, HashMap};
+use std::collections::{HashSet, HashMap, BTreeMap};
 use substrate_test_runtime_client::{
 	runtime::{Index, AccountId, Block, BlockNumber, Extrinsic, Hash, Header, Transfer},
 	AccountKeyring::{self, *},
 };
+use sp_blockchain::CachedHeaderMetadata;
 
 /// Error type used by [`TestApi`].
 #[derive(Debug, derive_more::From, derive_more::Display)]
@@ -53,9 +54,8 @@ impl std::error::Error for Error {
 
 #[derive(Default)]
 pub struct ChainState {
-	pub block_by_number: HashMap<BlockNumber, Vec<Extrinsic>>,
-	pub block_by_hash: HashMap<Hash, Vec<Extrinsic>>,
-	pub header_by_number: HashMap<BlockNumber, Header>,
+	pub block_by_number: BTreeMap<BlockNumber, Vec<Block>>,
+	pub block_by_hash: HashMap<Hash, Block>,
 	pub nonces: HashMap<AccountId, u64>,
 	pub invalid_hashes: HashSet<Hash>,
 }
@@ -70,11 +70,7 @@ pub struct TestApi {
 impl TestApi {
 	/// Test Api with Alice nonce set initially.
 	pub fn with_alice_nonce(nonce: u64) -> Self {
-		let api = TestApi {
-			valid_modifier: RwLock::new(Box::new(|_| {})),
-			chain: Default::default(),
-			validation_requests: RwLock::new(Default::default()),
-		};
+		let api = Self::empty();
 
 		api.chain.write().nonces.insert(Alice.into(), nonce);
 
@@ -89,6 +85,9 @@ impl TestApi {
 			validation_requests: RwLock::new(Default::default()),
 		};
 
+		// Push genesis block
+		api.push_block(0, Vec::new());
+
 		api
 	}
 
@@ -97,46 +96,61 @@ impl TestApi {
 		*self.valid_modifier.write() = modifier;
 	}
 
-	/// Push block as a part of canonical chain under given number.
+	/// Push block under given number.
+	///
+	/// If multiple blocks exists with the same block number, the first inserted block will be
+	/// interpreted as part of the canonical chain.
 	pub fn push_block(&self, block_number: BlockNumber, xts: Vec<Extrinsic>) -> Header {
-		let mut chain = self.chain.write();
-		chain.block_by_number.insert(block_number, xts.clone());
-		let header = Header {
-			number: block_number,
-			digest: Default::default(),
-			extrinsics_root:  Default::default(),
-			parent_hash: block_number
+		let parent_hash = {
+			let chain = self.chain.read();
+			block_number
 				.checked_sub(1)
 				.and_then(|num| {
-					chain.header_by_number.get(&num)
-						.cloned().map(|h| h.hash())
-				}).unwrap_or_default(),
-			state_root: Default::default(),
+					chain.block_by_number
+						.get(&num)
+						.map(|blocks| {
+							blocks[0].header.hash()
+						})
+				}).unwrap_or_default()
 		};
-		chain.block_by_hash.insert(header.hash(), xts);
-		chain.header_by_number.insert(block_number, header.clone());
-		header
+
+		self.push_block_with_parent(parent_hash, xts)
 	}
 
-	/// Push a block without a number.
+	/// Push a block using the given `parent`.
 	///
-	/// As a part of non-canonical chain.
-	pub fn push_fork_block(&self, block_hash: Hash, xts: Vec<Extrinsic>) {
+	/// Panics if `parent` does not exists.
+	pub fn push_block_with_parent(
+		&self,
+		parent: Hash,
+		xts: Vec<Extrinsic>,
+	) -> Header {
 		let mut chain = self.chain.write();
-		chain.block_by_hash.insert(block_hash, xts);
-	}
 
-	pub fn push_fork_block_with_parent(&self, parent: Hash, xts: Vec<Extrinsic>) -> Header {
-		let mut chain = self.chain.write();
-		let blocknum = chain.block_by_number.keys().max().expect("block_by_number shouldn't be empty");
+		// `Hash::default()` is the genesis parent hash
+		let block_number = if parent == Hash::default() {
+			0
+		} else {
+			*chain.block_by_hash
+				.get(&parent)
+				.expect("`parent` exists")
+				.header()
+				.number() + 1
+		};
+
 		let header = Header {
-			number: *blocknum,
+			number: block_number,
 			digest: Default::default(),
-			extrinsics_root:  Default::default(),
+			extrinsics_root: Hash::random(),
 			parent_hash: parent,
 			state_root: Default::default(),
 		};
-		chain.block_by_hash.insert(header.hash(), xts);
+
+		let hash = header.hash();
+		let block = Block::new(header.clone(), xts);
+		chain.block_by_hash.insert(hash, block.clone());
+		chain.block_by_number.entry(block_number).or_default().push(block);
+
 		header
 	}
 
@@ -170,11 +184,19 @@ impl TestApi {
 		let mut chain = self.chain.write();
 		chain.nonces.entry(account).and_modify(|n| *n += 1).or_insert(1);
 	}
+
+	/// Calculate a tree route between the two given blocks.
+	pub fn tree_route(
+		&self,
+		from: Hash,
+		to: Hash,
+	) -> Result<sp_blockchain::TreeRoute<Block>, Error> {
+		sp_blockchain::tree_route(self, from, to)
+	}
 }
 
 impl sc_transaction_graph::ChainApi for TestApi {
 	type Block = Block;
-	type Hash = Hash;
 	type Error = Error;
 	type ValidationFuture = futures::future::Ready<Result<TransactionValidity, Error>>;
 	type BodyFuture = futures::future::Ready<Result<Option<Vec<Extrinsic>>, Error>>;
@@ -218,7 +240,14 @@ impl sc_transaction_graph::ChainApi for TestApi {
 		&self,
 		at: &BlockId<Self::Block>,
 	) -> Result<Option<sc_transaction_graph::NumberFor<Self>>, Error> {
-		Ok(Some(number_of(at)))
+		Ok(match at {
+			generic::BlockId::Hash(x) => self.chain
+				.read()
+				.block_by_hash
+				.get(x)
+				.map(|b| *b.header.number()),
+			generic::BlockId::Number(num) => Some(*num),
+		})
 	}
 
 	fn block_id_to_hash(
@@ -227,34 +256,60 @@ impl sc_transaction_graph::ChainApi for TestApi {
 	) -> Result<Option<sc_transaction_graph::BlockHash<Self>>, Error> {
 		Ok(match at {
 			generic::BlockId::Hash(x) => Some(x.clone()),
-			generic::BlockId::Number(num) => {
-				self.chain.read()
-					.header_by_number.get(num)
-					.map(|h| h.hash())
-					.or_else(|| Some(Default::default()))
-			},
+			generic::BlockId::Number(num) => self.chain
+				.read()
+				.block_by_number
+				.get(num)
+				.map(|blocks| blocks[0].header().hash()),
 		})
 	}
 
 	fn hash_and_length(
 		&self,
 		ex: &sc_transaction_graph::ExtrinsicFor<Self>,
-	) -> (Self::Hash, usize) {
+	) -> (Hash, usize) {
 		Self::hash_and_length_inner(ex)
 	}
 
 	fn block_body(&self, id: &BlockId<Self::Block>) -> Self::BodyFuture {
 		futures::future::ready(Ok(match id {
-			BlockId::Number(num) => self.chain.read().block_by_number.get(num).cloned(),
-			BlockId::Hash(hash) => self.chain.read().block_by_hash.get(hash).cloned(),
+			BlockId::Number(num) => self.chain
+				.read()
+				.block_by_number
+				.get(num)
+				.map(|b| b[0].extrinsics().to_vec()),
+			BlockId::Hash(hash) => self.chain
+				.read()
+				.block_by_hash
+				.get(hash)
+				.map(|b| b.extrinsics().to_vec()),
 		}))
 	}
 }
 
-fn number_of(at: &BlockId<Block>) -> u64 {
-	match at {
-		generic::BlockId::Number(n) => *n as u64,
-		_ => 0,
+impl sp_blockchain::HeaderMetadata<Block> for TestApi {
+	type Error = Error;
+
+	fn header_metadata(
+		&self,
+		hash: Hash,
+	) -> Result<CachedHeaderMetadata<Block>, Self::Error> {
+		let chain = self.chain.read();
+		let block = chain.block_by_hash.get(&hash).expect("Hash exists");
+
+		Ok(block.header().into())
+	}
+
+	fn insert_header_metadata(
+		&self,
+		_: Hash,
+		_: CachedHeaderMetadata<Block>,
+	) {
+		unimplemented!("Not implemented for tests")
+	}
+
+	fn remove_header_metadata(&self, _: Hash) {
+		unimplemented!("Not implemented for tests")
 	}
 }
 
diff --git a/utils/frame/rpc/system/src/lib.rs b/utils/frame/rpc/system/src/lib.rs
index 415f9541b60bd..a3ce1466f6fe9 100644
--- a/utils/frame/rpc/system/src/lib.rs
+++ b/utils/frame/rpc/system/src/lib.rs
@@ -222,16 +222,14 @@ mod tests {
 	use super::*;
 
 	use futures::executor::block_on;
-	use substrate_test_runtime_client::{
-		runtime::Transfer,
-		AccountKeyring,
-	};
+	use substrate_test_runtime_client::{runtime::Transfer, AccountKeyring};
 	use sc_transaction_pool::{BasicPool, FullChainApi};
 
 	#[test]
 	fn should_return_next_nonce_for_some_account() {
-		// given
 		let _ = env_logger::try_init();
+
+		// given
 		let client = Arc::new(substrate_test_runtime_client::new());
 		let pool = Arc::new(
 			BasicPool::new(