diff --git a/app/models/case_log.rb b/app/models/case_log.rb
index 8fad9709c..934ec42a8 100644
--- a/app/models/case_log.rb
+++ b/app/models/case_log.rb
@@ -39,6 +39,16 @@ class CaseLogValidator < ActiveModel::Validator
     end
   end
 
+  def validate_armed_forces_injured(record)
+    if (record.armed_forces == "Yes - a regular" || record.armed_forces == "Yes - a reserve") && record.armed_forces_injured.blank?
+      record.errors.add :armed_forces_injured, "You must answer the armed forces injury question if the tenant has served in the armed forces"
+    end
+
+    if (record.armed_forces == "No" || record.armed_forces == "Prefer not to say") && record.armed_forces_injured.present?
+      record.errors.add :armed_forces_injured, "You must not answer the armed forces injury question if the tenant has not served in the armed forces or prefer not to say was chosen"
+    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 120c7947c..3967bc221 100644
--- a/spec/helpers/check_answers_helper_spec.rb
+++ b/spec/helpers/check_answers_helper_spec.rb
@@ -11,7 +11,7 @@ RSpec.describe CheckAnswersHelper do
     )
   end
   let(:case_log_with_met_radio_condition) do
-    FactoryBot.create(:case_log, armed_forces: "Yes - a regular")
+    FactoryBot.create(:case_log, armed_forces: "Yes - a regular", armed_forces_injured: "No")
   end
   let(:subsection) { "income_and_benefits" }
   let(:subsection_with_numeric_conditionals) { "household_characteristics" }
diff --git a/spec/models/case_log_spec.rb b/spec/models/case_log_spec.rb
index d3e4d74a9..927b153d1 100644
--- a/spec/models/case_log_spec.rb
+++ b/spec/models/case_log_spec.rb
@@ -26,7 +26,7 @@ RSpec.describe Form, type: :model do
       expect { CaseLog.create!(property_number_of_times_relet: 0) }.to raise_error(ActiveRecord::RecordInvalid)
     end
 
-    describe "reasonable preference validation" do
+    context "reasonable preference validation" do
       it "if given reasonable preference is yes a reason must be selected" do
         expect {
           CaseLog.create!(reasonable_preference: "Yes",
@@ -57,6 +57,7 @@ RSpec.describe Form, type: :model do
         }.to raise_error(ActiveRecord::RecordInvalid)
       end
     end
+
     context "other reason for leaving last settled home validation" do
       it "must be provided if main reason for leaving last settled home was given as other" do
         expect {
@@ -72,6 +73,22 @@ RSpec.describe Form, type: :model do
         }.to raise_error(ActiveRecord::RecordInvalid)
       end
     end
+
+    context "armed forces injured validation" do
+      it "must be anwered if tenant was a regular or reserve in armed forces" do
+        expect {
+          CaseLog.create!(armed_forces: "Yes - a regular",
+                          armed_forces_injured: nil)
+        }.to raise_error(ActiveRecord::RecordInvalid)
+      end
+
+      it "must be anwered if tenant was not a regular or reserve in armed forces" do
+        expect {
+          CaseLog.create!(armed_forces: "No",
+                          armed_forces_injured: "Yes")
+        }.to raise_error(ActiveRecord::RecordInvalid)
+      end
+    end
   end
 
   describe "status" do