diff --git a/app/models/case_log.rb b/app/models/case_log.rb
index 4b9d196b9..3657628ae 100644
--- a/app/models/case_log.rb
+++ b/app/models/case_log.rb
@@ -6,6 +6,7 @@ class CaseLogValidator < ActiveModel::Validator
   include Validations::FinancialValidations
   include Validations::TenancyValidations
   include Validations::DateValidations
+  include Validations::LocalAuthorityValidations
 
   def validate(record)
     validation_methods = public_methods.select { |method| method.starts_with?("validate_") }
diff --git a/app/models/validations/local_authority_validations.rb b/app/models/validations/local_authority_validations.rb
new file mode 100644
index 000000000..cae230900
--- /dev/null
+++ b/app/models/validations/local_authority_validations.rb
@@ -0,0 +1,11 @@
+module Validations::LocalAuthorityValidations
+  POSTCODE_REGEXP = Validations::PropertyValidations::POSTCODE_REGEXP
+
+  def validate_previous_accommodation_postcode(record)
+    postcode = record.previous_postcode
+    if postcode.present? && !postcode.match(POSTCODE_REGEXP)
+      error_message = "Enter a postcode in the correct format, for example AA1 1AA"
+      record.errors.add :previous_postcode, error_message
+    end
+  end
+end
diff --git a/app/models/validations/property_validations.rb b/app/models/validations/property_validations.rb
index 158b237cb..4d6792cd5 100644
--- a/app/models/validations/property_validations.rb
+++ b/app/models/validations/property_validations.rb
@@ -3,7 +3,7 @@ module Validations::PropertyValidations
   # or 'validate_' to run on submit as well
   include Constants::CaseLog
 
-  POSTCODE_REGEXP = /^(([A-Z]{1,2}[0-9][A-Z0-9]?|ASCN|STHL|TDCU|BBND|[BFS]IQQ|PCRN|TKCA) ?[0-9][A-Z]{2}|BFPO ?[0-9]{1,4}|(KY[0-9]|MSR|VG|AI)[ -]?[0-9]{4}|[A-Z]{2} ?[0-9]{2}|GE ?CX|GIR ?0A{2}|SAN ?TA1)$/
+  POSTCODE_REGEXP = /^(([A-Z]{1,2}[0-9][A-Z0-9]?|ASCN|STHL|TDCU|BBND|[BFS]IQQ|PCRN|TKCA) ?[0-9][A-Z]{2}|BFPO ?[0-9]{1,4}|(KY[0-9]|MSR|VG|AI)[ -]?[0-9]{4}|[A-Z]{2} ?[0-9]{2}|GE ?CX|GIR ?0A{2}|SAN ?TA1)$/i
 
   def validate_property_number_of_times_relet(record)
     if record.offered && !/^[1-9]$|^0[1-9]$|^1[0-9]$|^20$/.match?(record.offered.to_s)
diff --git a/spec/models/validations/local_authority_validations_spec.rb b/spec/models/validations/local_authority_validations_spec.rb
new file mode 100644
index 000000000..c62607e2a
--- /dev/null
+++ b/spec/models/validations/local_authority_validations_spec.rb
@@ -0,0 +1,56 @@
+require "rails_helper"
+require_relative "../../request_helper"
+
+RSpec.describe CaseLog do
+  let(:owning_organisation) { FactoryBot.create(:organisation) }
+  let(:managing_organisation) { owning_organisation }
+
+  before do
+    RequestHelper.stub_http_requests
+  end
+
+  describe "#new" do
+    it "raises an error when previous_postcode is present and invalid" do
+      expect {
+        CaseLog.create!(
+          previous_postcode: "invalid_postcode",
+          owning_organisation: owning_organisation,
+          managing_organisation: managing_organisation,
+        )
+      }.to raise_error(ActiveRecord::RecordInvalid, /Enter a postcode in the correct format/)
+    end
+  end
+end
+
+RSpec.describe Validations::LocalAuthorityValidations do
+  let(:subject) { subject_class.new }
+  let(:subject_class) { Class.new { include Validations::LocalAuthorityValidations } }
+  let(:record) { FactoryBot.create(:case_log) }
+
+  describe "#validate_previous_accommodation_postcode" do
+    it "does not add an error if the record previous_postcode is missing" do
+      record.previous_postcode = nil
+      subject.validate_previous_accommodation_postcode(record)
+      expect(record.errors).to be_empty
+    end
+
+    it "does not add an error if the record previous_postcode is valid (uppercase space)" do
+      record.previous_postcode = "M1 1AE"
+      subject.validate_previous_accommodation_postcode(record)
+      expect(record.errors).to be_empty
+    end
+
+    it "does not add an error if the record previous_postcode is valid (lowercase no space)" do
+      record.previous_postcode = "m11ae"
+      subject.validate_previous_accommodation_postcode(record)
+      expect(record.errors).to be_empty
+    end
+
+    it "does add an error when the postcode is invalid" do
+      record.previous_postcode = "invalid"
+      subject.validate_previous_accommodation_postcode(record)
+      expect(record.errors).to_not be_empty
+      expect(record.errors["previous_postcode"]).to include(match /Enter a postcode in the correct format/)
+    end
+  end
+end