diff --git a/app/models/case_log.rb b/app/models/case_log.rb
index aad4d23b0..f56f20e2f 100644
--- a/app/models/case_log.rb
+++ b/app/models/case_log.rb
@@ -55,6 +55,17 @@ class CaseLogValidator < ActiveModel::Validator
     end
   end
 
+  def validate_armed_forces_active_response(record)
+    # binding.pry
+    if record.armed_forces == "Yes - a regular" && record.armed_forces_active.blank?
+      record.errors.add :armed_forces_active, "You must answer the armed forces active question if the tenant has served as a regular in the armed forces"
+    end
+
+    if record.armed_forces != "Yes - a regular" && !record.armed_forces_active.blank?
+      record.errors.add :armed_forces_active, "You must not answer the armed forces active question if the tenant has not served as a regular in the armed forces"
+    end
+  end
+
   def validate(record)
     # If we've come from the form UI we only want to validate the specific fields
     # that have just been submitted. If we're submitting a log via API or Bulk Upload
diff --git a/spec/helpers/check_answers_helper_spec.rb b/spec/helpers/check_answers_helper_spec.rb
index cc619a041..e53c54957 100644
--- a/spec/helpers/check_answers_helper_spec.rb
+++ b/spec/helpers/check_answers_helper_spec.rb
@@ -11,7 +11,9 @@ RSpec.describe CheckAnswersHelper do
     )
   end
   let(:case_log_with_met_radio_condition) do
-    FactoryBot.create(:case_log, armed_forces: "Yes - a regular", armed_forces_injured: "No")
+    FactoryBot.create(:case_log, armed_forces: "Yes - a regular",
+      armed_forces_injured: "No",
+      armed_forces_active: "Yes")
   end
   let(:subsection) { "income_and_benefits" }
   let(:subsection_with_numeric_conditionals) { "household_characteristics" }
@@ -56,7 +58,7 @@ RSpec.describe CheckAnswersHelper do
                subsection_with_radio_conditionals,
                case_log_with_met_radio_condition,
                form,
-             )).to equal(3)
+             )).to equal(4)
     end
   end
 
diff --git a/spec/models/case_log_spec.rb b/spec/models/case_log_spec.rb
index 265296e40..5fcb41bec 100644
--- a/spec/models/case_log_spec.rb
+++ b/spec/models/case_log_spec.rb
@@ -96,6 +96,31 @@ RSpec.describe Form, type: :model do
         }.to raise_error(ActiveRecord::RecordInvalid)
       end
     end
+
+    context "armed forces active validation" do
+      it "must be answered if ever served in the forces as a regular" do
+        expect {
+          CaseLog.create!(armed_forces: "Yes - a regular",
+                          armed_forces_active: nil)
+        }.to raise_error(ActiveRecord::RecordInvalid)
+      end
+
+      it "must not be answered if not ever served as a regular" do
+        expect {
+          CaseLog.create!(armed_forces: "No",
+                          armed_forces_active: "Yes")
+        }.to raise_error()
+      end
+
+      #Crossover over tests here as injured must be answered as well for no error
+      it "must be answered if ever served in the forces as a regular" do
+        expect {
+          CaseLog.create!(armed_forces: "Yes - a regular",
+                          armed_forces_active: "Yes",
+                          armed_forces_injured: "Yes")
+        }.not_to raise_error()
+      end
+    end
   end
 
   describe "status" do