diff --git a/app/models/validations/local_authority_validations.rb b/app/models/validations/local_authority_validations.rb
index 0409572b9..e02394fe9 100644
--- a/app/models/validations/local_authority_validations.rb
+++ b/app/models/validations/local_authority_validations.rb
@@ -18,7 +18,9 @@ module Validations::LocalAuthorityValidations
         record.la && !record.owning_organisation.local_authorities.include?(record.la)
       la_name = record.form.get_question("la", record).label_from_value(record.la)
       org_name = record.owning_organisation.name
+      postcode = UKPostcode.parse(record.postcode_full) if record.postcode_full
       record.errors.add :la, I18n.t("validations.property.la.la_invalid_for_org", org_name:, la_name:)
+      record.errors.add :postcode_known, I18n.t("validations.property.la.postcode_invalid_for_org", org_name:, postcode:)
     end
   end
 end
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 5a2b36387..456ce9805 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -69,6 +69,7 @@ en:
       la:
         la_known: "Enter name of local authority"
         la_invalid_for_org: "%{org_name} does not operate in %{la_name}"
+        postcode_invalid_for_org: "Postcode must be in an area covered by %{org_name}"
       rsnvac:
         first_let_not_social: "Reason for vacancy cannot be first let if unit has been previously let as social housing"
         first_let_social: "Reason for vacancy must be first let if unit has been previously let as social housing"
diff --git a/spec/models/validations/local_authority_validations_spec.rb b/spec/models/validations/local_authority_validations_spec.rb
index 1ad97a72f..42c816c06 100644
--- a/spec/models/validations/local_authority_validations_spec.rb
+++ b/spec/models/validations/local_authority_validations_spec.rb
@@ -37,15 +37,6 @@ RSpec.describe Validations::LocalAuthorityValidations do
   end
 
   describe "#validate_la" do
-    context "when the rent type is London affordable" do
-      it "expects that the local authority is in London" do
-        record.la = "E09000033"
-        record.rent_type = 2
-        local_auth_validator.validate_la(record)
-        expect(record.errors["la"]).to be_empty
-      end
-    end
-
     context "when previous la is known" do
       it "la has to be provided" do
         record.la_known = 1
@@ -80,6 +71,20 @@ RSpec.describe Validations::LocalAuthorityValidations do
         local_auth_validator.validate_la(record)
         expect(record.errors["la"]).to be_empty
       end
+
+      context "when a postcode is given" do
+        it "validates that it matches a local authority the organisation operates in" do
+          record.postcode_full = "YO10 3RR"
+          record.la = "E06000014"
+          local_auth_validator.validate_la(record)
+          expect(record.errors["postcode_known"])
+            .to include(match I18n.t(
+              "validations.property.la.postcode_invalid_for_org",
+              org_name: organisation.name,
+              postcode: "YO10 3RR",
+            ))
+        end
+      end
     end
 
     context "when the organisation has not listed specific local authorities it operates in" do