diff --git a/spyder/plugins/ipythonconsole/__init__.py b/spyder/plugins/ipythonconsole/__init__.py
index 2ff34ccd29d..de5cf9b96d7 100644
--- a/spyder/plugins/ipythonconsole/__init__.py
+++ b/spyder/plugins/ipythonconsole/__init__.py
@@ -44,5 +44,12 @@
 
 
 class SpyderKernelError(RuntimeError):
-    """Error to be shown in client."""
-    pass
+    """
+    Error to be shown in the IPython console.
+
+    Notes
+    -----
+    * Use this exception if you want to show a nice formatted error in the
+      current console instead of a long and hard-to-read traceback.
+    * This should only be used for errors whose cause we are certain of.
+    """
diff --git a/spyder/plugins/ipythonconsole/utils/client.py b/spyder/plugins/ipythonconsole/utils/client.py
index 7f10a69bc5d..57fa71e2bf7 100644
--- a/spyder/plugins/ipythonconsole/utils/client.py
+++ b/spyder/plugins/ipythonconsole/utils/client.py
@@ -20,6 +20,7 @@
 # Local imports
 from spyder.api.asyncdispatcher import AsyncDispatcher
 from spyder.api.translations import _
+from spyder.plugins.ipythonconsole import SpyderKernelError
 
 
 class KernelClientTunneler:
@@ -63,10 +64,10 @@ async def forward_port(self, remote_host, remote_port):
                 )
             )
         except asyncssh.Error as err:
-            raise RuntimeError(
+            raise SpyderKernelError(
                 _(
-                    "It was not possible to open an SSH tunnel for the "
-                    "remote kernel. Please check your credentials and the "
+                    "It was not possible to open an SSH tunnel to connect to "
+                    "the remote kernel. Please check your credentials and the "
                     "server connection status."
                 )
             ) from err
diff --git a/spyder/plugins/ipythonconsole/utils/kernel_handler.py b/spyder/plugins/ipythonconsole/utils/kernel_handler.py
index 10dada739d9..b8a9f73f305 100644
--- a/spyder/plugins/ipythonconsole/utils/kernel_handler.py
+++ b/spyder/plugins/ipythonconsole/utils/kernel_handler.py
@@ -27,6 +27,7 @@
     SPYDER_KERNELS_VERSION,
     SPYDER_KERNELS_CONDA,
     SPYDER_KERNELS_PIP,
+    SpyderKernelError,
 )
 from spyder.plugins.ipythonconsole.comms.kernelcomm import KernelComm
 from spyder.plugins.ipythonconsole.utils.manager import SpyderKernelManager
@@ -35,8 +36,8 @@
 
 
 PERMISSION_ERROR_MSG = _(
-    "The directory {} is not writable and it is required to create IPython "
-    "consoles. Please make it writable."
+    "The directory <tt>{}</tt> is not writable and it is required to create "
+    "IPython consoles. Please make it writable."
 )
 
 ERROR_SPYDER_KERNEL_VERSION = _(
@@ -377,7 +378,7 @@ def new_from_spec(cls, kernel_spec):
         """
         connection_file = cls.new_connection_file()
         if connection_file is None:
-            raise RuntimeError(
+            raise SpyderKernelError(
                 PERMISSION_ERROR_MSG.format(jupyter_runtime_dir())
             )
 
@@ -390,11 +391,19 @@ def new_from_spec(cls, kernel_spec):
 
         kernel_manager._kernel_spec = kernel_spec
 
-        kernel_manager.start_kernel(
-            stderr=PIPE,
-            stdout=PIPE,
-            env=kernel_spec.env,
-        )
+        try:
+            kernel_manager.start_kernel(
+                stderr=PIPE,
+                stdout=PIPE,
+                env=kernel_spec.env,
+            )
+        except PermissionError:
+            # Show a nice error message when jupyter_runtime_dir is not
+            # writable.
+            # Fixes spyder-ide/spyder#23124
+            raise SpyderKernelError(
+                PERMISSION_ERROR_MSG.format(jupyter_runtime_dir())
+            )
 
         # Kernel client
         kernel_client = kernel_manager.client()
@@ -474,13 +483,13 @@ def init_kernel_client(
         try:
             kernel_client.load_connection_file()
         except Exception as e:
-            raise RuntimeError(
+            raise SpyderKernelError(
                 _(
                     "An error occurred while trying to load "
                     "the kernel connection file. The error "
                     "was:\n\n"
                 )
-                + str(e)
+                + f"<tt>{str(e)}</tt>"
             )
 
         if hostname is not None or ssh_connection is not None: