Apply the feature flag

app/policies/project_policy.rb

@@ -123,6 +123,11 @@ class ProjectPolicy < BasePolicy
     !@subject.design_management_enabled?
   end
 
+  with_scope :global
+  condition(:moving_designs_disabled) do
+    !::Feature.enabled?(:reorder_designs)
+  end
+
   with_scope :subject
   condition(:service_desk_enabled) { @subject.service_desk_enabled? }
 
@@ -577,6 +582,10 @@ class ProjectPolicy < BasePolicy
     prevent :move_design
   end
 
+  rule { moving_designs_disabled }.policy do
+    prevent :move_design
+  end
+
   rule { read_package_registry_deploy_token }.policy do
     enable :read_package
     enable :read_project

spec/policies/design_management/design_policy_spec.rb

@@ -131,6 +131,17 @@ RSpec.describe DesignManagement::DesignPolicy do
 
     it_behaves_like "design abilities available for members"
 
+    context 'when reorder_designs is not enabled' do
+      before do
+        stub_feature_flags(reorder_designs: false)
+      end
+
+      let(:current_user) { developer }
+
+      it { is_expected.to be_allowed(*(developer_design_abilities - [:move_design])) }
+      it { is_expected.to be_disallowed(:move_design) }
+    end
+
     context "for guests in private projects" do
       let_it_be(:project) { create(:project, :private) }
       let(:current_user) { guest }