diff --git a/plugins/locale-observer.js b/plugins/locale-observer.js
index 308f0f812..a48a5fe9d 100644
--- a/plugins/locale-observer.js
+++ b/plugins/locale-observer.js
@@ -1,13 +1,27 @@
-import { setCookie } from '~/services/cookie'
+import { getCookie, setCookie } from '~/services/cookie'
 
 export default function (context) {
   const { app, isDev } = context
   app.i18n.onBeforeLanguageSwitch = (oldLocale, newLocale) => {
     _setLocaleCookie(newLocale, isDev)
   }
+
+  _handleLocaleCookie(isDev)
 }
 
 function _setLocaleCookie(locale, isDev) {
   const canonicalName = Intl.getCanonicalLocales(locale)?.[0]
   setCookie('locale', canonicalName, isDev)
 }
+
+function _handleLocaleCookie(isDev) {
+  const localeCookie = getCookie('locale')
+
+  if (!localeCookie) return
+
+  try {
+    if (Intl.getCanonicalLocales(localeCookie)[0] === 'en-GB') {
+      setCookie('locale', 'en', isDev)
+    }
+  } catch (error) {}
+}
diff --git a/tests/plugins/locale-observer.test.js b/tests/plugins/locale-observer.test.js
index 136effe68..a39639467 100644
--- a/tests/plugins/locale-observer.test.js
+++ b/tests/plugins/locale-observer.test.js
@@ -70,6 +70,31 @@ describe('Plugins | locale-observer', () => {
         )
       })
     })
+
+    describe('when user already has an "en-GB" locale cookie value', () => {
+      it('updates locale cookie value with "en"', () => {
+        // given
+        document.cookie =
+          'locale=en-GB; path=/; max-age=31536000; SameSite=Strict'
+        const context = {
+          isDev: true,
+          app: {
+            i18n: {},
+          },
+          route: {
+            path: '/',
+          },
+        }
+
+        // when
+        localeObserver(context)
+
+        // then
+        expect(document.cookie).toEqual(
+          'locale=en; path=/; max-age=31536000; SameSite=Strict'
+        )
+      })
+    })
   })
 
   describe('when in production mode', () => {