diff --git a/lib/locales/en-GB.yml b/lib/locales/en-GB.yml
index b8aa870dc0..c6ec2242b6 100644
--- a/lib/locales/en-GB.yml
+++ b/lib/locales/en-GB.yml
@@ -1,7 +1,13 @@
 en-GB:
   faker:
     address:
-      postcode: "/[A-PR-UWYZ]([A-HK-Y][0-9][ABEHMNPRVWXY0-9]?|[0-9][ABCDEFGHJKPSTUW0-9]?) [0-9][ABD-HJLNP-UW-Z]{2}/"
+      postcode:
+        - "/[A-PR-UWYZ][0-9] [0-9][ABD-HJLNP-UW-Z]{2}/"                      # AN NAA   (e.g. M1 1AA)
+        - "/[A-PR-UWYZ][0-9]{2} [0-9][ABD-HJLNP-UW-Z]{2}/"                   # ANN NAA  (e.g. M60 1NW)
+        - "/[A-PR-UWYZ][A-HK-Y][0-9] [0-9][ABD-HJLNP-UW-Z]{2}/"              # AAN NAA  (e.g. CR2 6XH)
+        - "/[A-PR-UWYZ][A-HK-Y][0-9]{2} [0-9][ABD-HJLNP-UW-Z]{2}/"           # AANN NAA (e.g. DN55 1PT)
+        - "/[A-PR-UWYZ][0-9][ABCDEFGHJKPSTUW] [0-9][ABD-HJLNP-UW-Z]{2}/"     # ANA NAA  (e.g. W1A 1HQ)
+        - "/[A-PR-UWYZ][A-HK-Y][0-9][ABEHMNPRVWXY] [0-9][ABD-HJLNP-UW-Z]{2}/" # AANA NAA (e.g. EC1A 1BB)
       county:
         - Avon
         - Bedfordshire
diff --git a/test/test_en_gb_locale.rb b/test/test_en_gb_locale.rb
index 8a921b0c86..907b1df5ca 100644
--- a/test/test_en_gb_locale.rb
+++ b/test/test_en_gb_locale.rb
@@ -54,6 +54,23 @@ def test_en_gb_postcode_has_outcode_and_incode
     assert_equal 2, postcode.split.length
   end
 
+  POSTCODE_FORMATS = Regexp.union(
+    /\A[A-PR-UWYZ][0-9] [0-9][ABD-HJLNP-UW-Z]{2}\z/,                      # AN NAA
+    /\A[A-PR-UWYZ][0-9]{2} [0-9][ABD-HJLNP-UW-Z]{2}\z/,                   # ANN NAA
+    /\A[A-PR-UWYZ][A-HK-Y][0-9] [0-9][ABD-HJLNP-UW-Z]{2}\z/,              # AAN NAA
+    /\A[A-PR-UWYZ][A-HK-Y][0-9]{2} [0-9][ABD-HJLNP-UW-Z]{2}\z/,           # AANN NAA
+    /\A[A-PR-UWYZ][0-9][ABCDEFGHJKPSTUW] [0-9][ABD-HJLNP-UW-Z]{2}\z/,     # ANA NAA
+    /\A[A-PR-UWYZ][A-HK-Y][0-9][ABEHMNPRVWXY] [0-9][ABD-HJLNP-UW-Z]{2}\z/ # AANA NAA
+  )
+
+  def test_en_gb_postcode_always_matches_a_valid_format
+    100.times do
+      postcode = Faker::Address.postcode
+
+      assert_match POSTCODE_FORMATS, postcode, "#{postcode.inspect} is not a valid UK postcode format"
+    end
+  end
+
   def test_en_gb_postcode_incode_is_valid
     # The letters C I K M O V are not used in the second part of the Postcode.
     incode = Faker::Address.postcode.split[1]