diff --git a/lambdas/backend-api/src/__tests__/app/routing-config-client.test.ts b/lambdas/backend-api/src/__tests__/app/routing-config-client.test.ts
index 7525052cd..3e0b1de0c 100644
--- a/lambdas/backend-api/src/__tests__/app/routing-config-client.test.ts
+++ b/lambdas/backend-api/src/__tests__/app/routing-config-client.test.ts
@@ -770,6 +770,8 @@ describe('RoutingConfigClient', () => {
     test('returns updated routing config', async () => {
       const { client, mocks } = setup();
 
+      const campaignId = 'campaign-1';
+
       const update: UpdateRoutingConfig = {
         cascade: [
           ...routingConfig.cascade,
@@ -801,6 +803,10 @@ describe('RoutingConfigClient', () => {
         },
       });
 
+      mocks.routingConfigRepository.get.mockResolvedValueOnce({
+        data: routingConfig,
+      });
+
       mocks.routingConfigRepository.update.mockResolvedValueOnce({
         data: updated,
       });
@@ -816,7 +822,8 @@ describe('RoutingConfigClient', () => {
         routingConfig.id,
         update,
         user,
-        42
+        42,
+        campaignId
       );
 
       expect(result).toEqual({
@@ -956,6 +963,10 @@ describe('RoutingConfigClient', () => {
         },
       });
 
+      mocks.routingConfigRepository.get.mockResolvedValueOnce({
+        data: routingConfig,
+      });
+
       const result = await client.updateRoutingConfig(
         routingConfig.id,
         update,
@@ -1010,6 +1021,51 @@ describe('RoutingConfigClient', () => {
         },
       });
     });
+
+    test('returns routingConfig error without updating when routing config fetch fails', async () => {
+      const { client, mocks } = setup();
+
+      const update = {
+        cascade: routingConfig.cascade,
+        cascadeGroupOverrides: routingConfig.cascadeGroupOverrides,
+        name: routingConfig.name,
+      } as unknown as UpdateRoutingConfig;
+
+      mocks.clientConfigRepository.get.mockResolvedValueOnce({
+        data: {
+          features: { routing: true },
+          campaignIds: [routingConfig.campaignId],
+        },
+      });
+
+      mocks.routingConfigRepository.get.mockResolvedValueOnce({
+        error: {
+          actualError: new Error('Routing config not found'),
+          errorMeta: {
+            code: 404,
+            description: 'Routing config not found',
+          },
+        },
+      });
+
+      const result = await client.updateRoutingConfig(
+        routingConfig.id,
+        update,
+        user,
+        '42'
+      );
+
+      expect(mocks.routingConfigRepository.update).not.toHaveBeenCalled();
+      expect(result).toEqual({
+        error: {
+          actualError: new Error('Routing config not found'),
+          errorMeta: {
+            code: 404,
+            description: 'Routing config not found',
+          },
+        },
+      });
+    });
   });
 
   describe('getRoutingConfigsByTemplateId', () => {
diff --git a/lambdas/backend-api/src/__tests__/infra/routing-config-repository/repository.test.ts b/lambdas/backend-api/src/__tests__/infra/routing-config-repository/repository.test.ts
index e5f1d3e2f..abc0bd3ca 100644
--- a/lambdas/backend-api/src/__tests__/infra/routing-config-repository/repository.test.ts
+++ b/lambdas/backend-api/src/__tests__/infra/routing-config-repository/repository.test.ts
@@ -1614,7 +1614,13 @@ describe('RoutingConfigRepository', () => {
       mocks.dynamo.on(TransactWriteCommand).resolves({});
       mocks.dynamo.on(GetCommand).resolves({ Item: updated });
 
-      const result = await repo.update(routingConfig.id, update, user, 2);
+      const result = await repo.update(
+        routingConfig.id,
+        update,
+        user,
+        2,
+        routingConfig.campaignId
+      );
 
       expect(result).toEqual({ data: updated });
 
@@ -1662,7 +1668,14 @@ describe('RoutingConfigRepository', () => {
                 id: '90e46ece-4a3b-47bd-b781-f986b42a5a09',
                 owner: clientOwnerKey,
               },
-              ConditionExpression: 'attribute_exists(id)',
+              ConditionExpression:
+                'attribute_exists(id) AND (templateType <> :letter OR campaignId = :expectedCampaignId)',
+              ExpressionAttributeValues: {
+                ':expectedCampaignId': routingConfig.campaignId,
+                ':letter': 'LETTER',
+              },
+              ReturnValuesOnConditionCheckFailure:
+                ReturnValuesOnConditionCheckFailure.ALL_OLD,
             },
           },
         ],
@@ -1692,7 +1705,13 @@ describe('RoutingConfigRepository', () => {
       mocks.dynamo.on(TransactWriteCommand).resolves({});
       mocks.dynamo.on(GetCommand).resolves({ Item: updated });
 
-      const result = await repo.update(routingConfig.id, update, user, 2);
+      const result = await repo.update(
+        routingConfig.id,
+        update,
+        user,
+        2,
+        routingConfig.campaignId
+      );
 
       expect(result).toEqual({ data: updated });
 
@@ -1764,7 +1783,13 @@ describe('RoutingConfigRepository', () => {
       mocks.dynamo.on(TransactWriteCommand).resolves({});
       mocks.dynamo.on(GetCommand).resolves({ Item: updated });
 
-      const result = await repo.update(routingConfig.id, update, user, 2);
+      const result = await repo.update(
+        routingConfig.id,
+        update,
+        user,
+        2,
+        routingConfig.campaignId
+      );
 
       expect(result).toEqual({ data: updated });
 
@@ -1810,7 +1835,14 @@ describe('RoutingConfigRepository', () => {
                 id: 'c003b4f1-d788-423d-a948-0df511d07a23',
                 owner: clientOwnerKey,
               },
-              ConditionExpression: 'attribute_exists(id)',
+              ConditionExpression:
+                'attribute_exists(id) AND (templateType <> :letter OR campaignId = :expectedCampaignId)',
+              ExpressionAttributeValues: {
+                ':expectedCampaignId': routingConfig.campaignId,
+                ':letter': 'LETTER',
+              },
+              ReturnValuesOnConditionCheckFailure:
+                ReturnValuesOnConditionCheckFailure.ALL_OLD,
             },
           },
         ],
@@ -1863,7 +1895,13 @@ describe('RoutingConfigRepository', () => {
       mocks.dynamo.on(TransactWriteCommand).resolves({});
       mocks.dynamo.on(GetCommand).resolves({ Item: updated });
 
-      const result = await repo.update(routingConfig.id, update, user, 2);
+      const result = await repo.update(
+        routingConfig.id,
+        update,
+        user,
+        2,
+        routingConfig.campaignId
+      );
 
       expect(result).toEqual({ data: updated });
 
@@ -1909,7 +1947,14 @@ describe('RoutingConfigRepository', () => {
                 id: 'default-template-id',
                 owner: clientOwnerKey,
               },
-              ConditionExpression: 'attribute_exists(id)',
+              ConditionExpression:
+                'attribute_exists(id) AND (templateType <> :letter OR campaignId = :expectedCampaignId)',
+              ExpressionAttributeValues: {
+                ':expectedCampaignId': routingConfig.campaignId,
+                ':letter': 'LETTER',
+              },
+              ReturnValuesOnConditionCheckFailure:
+                ReturnValuesOnConditionCheckFailure.ALL_OLD,
             },
           },
           {
@@ -1919,7 +1964,14 @@ describe('RoutingConfigRepository', () => {
                 id: 'conditional-template-1',
                 owner: clientOwnerKey,
               },
-              ConditionExpression: 'attribute_exists(id)',
+              ConditionExpression:
+                'attribute_exists(id) AND (templateType <> :letter OR campaignId = :expectedCampaignId)',
+              ExpressionAttributeValues: {
+                ':expectedCampaignId': routingConfig.campaignId,
+                ':letter': 'LETTER',
+              },
+              ReturnValuesOnConditionCheckFailure:
+                ReturnValuesOnConditionCheckFailure.ALL_OLD,
             },
           },
           {
@@ -1929,7 +1981,14 @@ describe('RoutingConfigRepository', () => {
                 id: 'conditional-template-2',
                 owner: clientOwnerKey,
               },
-              ConditionExpression: 'attribute_exists(id)',
+              ConditionExpression:
+                'attribute_exists(id) AND (templateType <> :letter OR campaignId = :expectedCampaignId)',
+              ExpressionAttributeValues: {
+                ':expectedCampaignId': routingConfig.campaignId,
+                ':letter': 'LETTER',
+              },
+              ReturnValuesOnConditionCheckFailure:
+                ReturnValuesOnConditionCheckFailure.ALL_OLD,
             },
           },
           {
@@ -1939,7 +1998,14 @@ describe('RoutingConfigRepository', () => {
                 id: 'accessible-template-1',
                 owner: clientOwnerKey,
               },
-              ConditionExpression: 'attribute_exists(id)',
+              ConditionExpression:
+                'attribute_exists(id) AND (templateType <> :letter OR campaignId = :expectedCampaignId)',
+              ExpressionAttributeValues: {
+                ':expectedCampaignId': routingConfig.campaignId,
+                ':letter': 'LETTER',
+              },
+              ReturnValuesOnConditionCheckFailure:
+                ReturnValuesOnConditionCheckFailure.ALL_OLD,
             },
           },
         ],
@@ -1977,7 +2043,13 @@ describe('RoutingConfigRepository', () => {
       mocks.dynamo.on(TransactWriteCommand).resolves({});
       mocks.dynamo.on(GetCommand).resolves({ Item: updated });
 
-      const result = await repo.update(routingConfig.id, update, user, 2);
+      const result = await repo.update(
+        routingConfig.id,
+        update,
+        user,
+        2,
+        routingConfig.campaignId
+      );
 
       expect(result).toEqual({ data: updated });
 
@@ -2021,7 +2093,14 @@ describe('RoutingConfigRepository', () => {
                 id: 'c003b4f1-d788-423d-a948-0df511d07a23',
                 owner: clientOwnerKey,
               },
-              ConditionExpression: 'attribute_exists(id)',
+              ConditionExpression:
+                'attribute_exists(id) AND (templateType <> :letter OR campaignId = :expectedCampaignId)',
+              ExpressionAttributeValues: {
+                ':expectedCampaignId': routingConfig.campaignId,
+                ':letter': 'LETTER',
+              },
+              ReturnValuesOnConditionCheckFailure:
+                ReturnValuesOnConditionCheckFailure.ALL_OLD,
             },
           },
         ],
@@ -2052,7 +2131,13 @@ describe('RoutingConfigRepository', () => {
       mocks.dynamo.on(TransactWriteCommand).resolves({});
       mocks.dynamo.on(GetCommand).resolves({ Item: updated });
 
-      const result = await repo.update(routingConfig.id, update, user, 2);
+      const result = await repo.update(
+        routingConfig.id,
+        update,
+        user,
+        2,
+        routingConfig.campaignId
+      );
 
       expect(result).toEqual({ data: updated });
 
@@ -2114,7 +2199,13 @@ describe('RoutingConfigRepository', () => {
       mocks.dynamo.on(TransactWriteCommand).resolves({});
       mocks.dynamo.on(GetCommand).resolves({ Item: routingConfig });
 
-      const result = await repo.update(routingConfig.id, update, user, 2);
+      const result = await repo.update(
+        routingConfig.id,
+        update,
+        user,
+        2,
+        routingConfig.campaignId
+      );
 
       expect(result).toEqual({ data: routingConfig });
 
@@ -2162,7 +2253,14 @@ describe('RoutingConfigRepository', () => {
                 id: '90e46ece-4a3b-47bd-b781-f986b42a5a09',
                 owner: clientOwnerKey,
               },
-              ConditionExpression: 'attribute_exists(id)',
+              ConditionExpression:
+                'attribute_exists(id) AND (templateType <> :letter OR campaignId = :expectedCampaignId)',
+              ExpressionAttributeValues: {
+                ':expectedCampaignId': routingConfig.campaignId,
+                ':letter': 'LETTER',
+              },
+              ReturnValuesOnConditionCheckFailure:
+                ReturnValuesOnConditionCheckFailure.ALL_OLD,
             },
           },
         ],
@@ -2192,7 +2290,8 @@ describe('RoutingConfigRepository', () => {
           name: routingConfig.name,
         },
         user,
-        2
+        2,
+        routingConfig.campaignId
       );
 
       expect(result).toEqual({
@@ -2225,7 +2324,8 @@ describe('RoutingConfigRepository', () => {
           name: routingConfig.name,
         },
         user,
-        2
+        2,
+        routingConfig.campaignId
       );
 
       expect(result).toEqual({
@@ -2269,7 +2369,8 @@ describe('RoutingConfigRepository', () => {
         routingConfig.id,
         { name: 'new-name' },
         user,
-        2
+        2,
+        routingConfig.campaignId
       );
 
       expect(result).toEqual({
@@ -2302,7 +2403,8 @@ describe('RoutingConfigRepository', () => {
         routingConfig.id,
         { name: 'new-name' },
         user,
-        2
+        2,
+        routingConfig.campaignId
       );
 
       expect(result).toEqual({
@@ -2335,7 +2437,8 @@ describe('RoutingConfigRepository', () => {
         routingConfig.id,
         { name: 'new name' },
         user,
-        2
+        2,
+        routingConfig.campaignId
       );
 
       expect(result).toEqual({
@@ -2372,7 +2475,8 @@ describe('RoutingConfigRepository', () => {
         routingConfig.id,
         { name: 'new-name' },
         user,
-        2
+        2,
+        routingConfig.campaignId
       );
 
       expect(result).toEqual({
@@ -2420,7 +2524,8 @@ describe('RoutingConfigRepository', () => {
           cascadeGroupOverrides: [],
         },
         user,
-        2
+        2,
+        routingConfig.campaignId
       );
 
       expect(result).toEqual({
@@ -2435,6 +2540,75 @@ describe('RoutingConfigRepository', () => {
       });
     });
 
+    test('returns 400 failure if some templates are invalid', async () => {
+      const { repo, mocks } = setup();
+
+      const err = new TransactionCanceledException({
+        CancellationReasons: [
+          {
+            Code: 'None', // Update succeeded
+          },
+          {
+            Code: 'ConditionalCheckFailed',
+            Item: { id: { S: 'template1' } }, // Invalid template
+          },
+          {
+            Code: 'ProvisionedThroughputExceeded', // should be ignored
+          },
+        ],
+        $metadata: {},
+        message: 'Transaction cancelled',
+      });
+
+      mocks.dynamo.on(TransactWriteCommand).rejects(err);
+
+      const result = await repo.update(
+        routingConfig.id,
+        {
+          name: 'new-name',
+          cascade: [
+            {
+              cascadeGroups: ['standard'],
+              channel: 'SMS',
+              channelType: 'primary',
+              defaultTemplateId: 'template1',
+            },
+            {
+              cascadeGroups: ['accessible'],
+              channel: 'EMAIL',
+              channelType: 'secondary',
+              conditionalTemplates: [
+                { templateId: 'template2', accessibleFormat: 'x1' },
+              ],
+            },
+            {
+              cascadeGroups: ['translations'],
+              channel: 'NHSAPP',
+              channelType: 'primary',
+              conditionalTemplates: [
+                { templateId: 'template3', language: 'ar' },
+              ],
+            },
+          ],
+          cascadeGroupOverrides: [],
+        },
+        user,
+        2,
+        routingConfig.campaignId
+      );
+
+      expect(result).toEqual({
+        error: {
+          actualError: err,
+          errorMeta: {
+            code: 400,
+            description: 'Some templates failed validation',
+            details: { templateIds: 'template1' },
+          },
+        },
+      });
+    });
+
     test('returns 500 failure if GetCommand fails after TransactWriteCommand succeeds', async () => {
       const { repo, mocks } = setup();
 
@@ -2447,7 +2621,8 @@ describe('RoutingConfigRepository', () => {
         routingConfig.id,
         { name: 'new-name' },
         user,
-        2
+        2,
+        routingConfig.campaignId
       );
 
       expect(result).toEqual({
@@ -2476,7 +2651,8 @@ describe('RoutingConfigRepository', () => {
         routingConfig.id,
         { name: 'new-name' },
         user,
-        2
+        2,
+        routingConfig.campaignId
       );
 
       expect(result).toEqual({
diff --git a/lambdas/backend-api/src/app/routing-config-client.ts b/lambdas/backend-api/src/app/routing-config-client.ts
index 04a8fc1b2..1c559f2f3 100644
--- a/lambdas/backend-api/src/app/routing-config-client.ts
+++ b/lambdas/backend-api/src/app/routing-config-client.ts
@@ -91,11 +91,17 @@ export class RoutingConfigClient {
 
     if (validationResult.error) return validationResult;
 
+    // Fetch routing config
+    const routingConfig = await this.getRoutingConfig(routingConfigId, user);
+
+    if (routingConfig.error) return routingConfig;
+
     return this.routingConfigRepository.update(
       routingConfigId,
       validationResult.data,
       user,
-      lockNumberValidation.data
+      lockNumberValidation.data,
+      routingConfig.data.campaignId
     );
   }
 
diff --git a/lambdas/backend-api/src/infra/routing-config-repository/repository.ts b/lambdas/backend-api/src/infra/routing-config-repository/repository.ts
index c9ed22ec5..f00c7e95e 100644
--- a/lambdas/backend-api/src/infra/routing-config-repository/repository.ts
+++ b/lambdas/backend-api/src/infra/routing-config-repository/repository.ts
@@ -97,7 +97,8 @@ export class RoutingConfigRepository {
     id: string,
     updateData: UpdateRoutingConfig,
     user: User,
-    lockNumber: number
+    lockNumber: number,
+    expectedCampaignId: string
   ): Promise<ApplicationResult<RoutingConfig>> {
     const { cascade, cascadeGroupOverrides, name } = updateData;
 
@@ -139,7 +140,14 @@ export class RoutingConfigRepository {
                   id: templateId,
                   owner: this.clientOwnerKey(user.clientId),
                 },
-                ConditionExpression: 'attribute_exists(id)',
+                ConditionExpression:
+                  'attribute_exists(id) AND (templateType <> :letter OR campaignId = :expectedCampaignId)',
+                ExpressionAttributeValues: {
+                  ':expectedCampaignId': expectedCampaignId,
+                  ':letter': 'LETTER',
+                },
+                ReturnValuesOnConditionCheckFailure:
+                  ReturnValuesOnConditionCheckFailure.ALL_OLD,
               },
             })),
           ],
@@ -558,16 +566,32 @@ export class RoutingConfigRepository {
       );
     }
 
-    const templatesMissing = templateReasons.some(
-      (r) => r.Code === 'ConditionalCheckFailed'
-    );
+    const notFoundTemplateIds: string[] = [];
+    const invalidTemplateIds: string[] = [];
 
-    if (templatesMissing) {
+    for (const [index, reason] of templateReasons.entries()) {
+      if (reason?.Code !== 'ConditionalCheckFailed') continue;
+      const templateId = templateIds[index];
+      if (reason.Item) {
+        invalidTemplateIds.push(templateId);
+      } else {
+        notFoundTemplateIds.push(templateId);
+      }
+    }
+    if (notFoundTemplateIds.length > 0) {
       return failure(
         ErrorCase.ROUTING_CONFIG_TEMPLATES_NOT_FOUND,
         'Some templates not found',
         err,
-        { templateIds: templateIds.join(',') }
+        { templateIds: notFoundTemplateIds.join(',') }
+      );
+    }
+    if (invalidTemplateIds.length > 0) {
+      return failure(
+        ErrorCase.ROUTING_CONFIG_TEMPLATES_INVALID,
+        'Some templates failed validation',
+        err,
+        { templateIds: invalidTemplateIds.join(',') }
       );
     }
 
diff --git a/tests/test-team/template-mgmt-api-tests/update-routing-config.api.spec.ts b/tests/test-team/template-mgmt-api-tests/update-routing-config.api.spec.ts
index 86a60cc7b..eb06639ad 100644
--- a/tests/test-team/template-mgmt-api-tests/update-routing-config.api.spec.ts
+++ b/tests/test-team/template-mgmt-api-tests/update-routing-config.api.spec.ts
@@ -675,4 +675,141 @@ test.describe('PATCH /v1/routing-configuration/:routingConfigId', () => {
         'Lock number mismatch - Routing configuration has been modified since last read',
     });
   });
+
+  test('update fails when adding template with a different campaignId to the routing campaignId', async ({
+    request,
+  }) => {
+    const { dbEntry } = RoutingConfigFactory.create(userMultiCampaign, {
+      campaignId: 'campaign-id',
+    });
+    const letterTemplate = TemplateFactory.createAuthoringLetterTemplate(
+      randomUUID(),
+      userMultiCampaign,
+      'Plan campaign mismatch template',
+      'PROOF_APPROVED',
+      {
+        letterVariantId: 'variant',
+        longFormRender: { status: 'RENDERED' },
+        shortFormRender: { status: 'RENDERED' },
+        campaignId: 'other-campaign-id',
+      }
+    );
+
+    await storageHelper.seed([dbEntry]);
+    await templateStorageHelper.seedTemplateData([letterTemplate]);
+
+    const update = {
+      cascade: [
+        {
+          cascadeGroups: ['accessible'],
+          channel: 'LETTER',
+          channelType: 'primary',
+          defaultTemplateId: letterTemplate.id,
+        },
+      ],
+      cascadeGroupOverrides: [],
+    };
+
+    const updateResponse = await request.patch(
+      `${process.env.API_BASE_URL}/v1/routing-configuration/${dbEntry.id}`,
+      {
+        headers: {
+          Authorization: await userMultiCampaign.getAccessToken(),
+          'X-Lock-Number': String(dbEntry.lockNumber),
+        },
+        data: update,
+      }
+    );
+
+    expect(updateResponse.status()).toBe(400);
+
+    const updated = await updateResponse.json();
+
+    expect(updated).toEqual({
+      statusCode: 400,
+      technicalMessage: 'Some templates failed validation',
+      details: {
+        templateIds: letterTemplate.id,
+      },
+    });
+  });
+
+  test('update fails when adding multiple templates where at least one template does not belong to the routing config campaign', async ({
+    request,
+  }) => {
+    const { dbEntry } = RoutingConfigFactory.create(userMultiCampaign, {
+      campaignId: 'campaign-id',
+    });
+    const letterTemplate1 = TemplateFactory.createAuthoringLetterTemplate(
+      randomUUID(),
+      userMultiCampaign,
+      'Plan campaign mismatch template - matching campaign',
+      'PROOF_APPROVED',
+      {
+        letterVariantId: 'variant',
+        longFormRender: { status: 'RENDERED' },
+        shortFormRender: { status: 'RENDERED' },
+        campaignId: 'campaign-id',
+      }
+    );
+    const letterTemplate2 = TemplateFactory.createAuthoringLetterTemplate(
+      randomUUID(),
+      userMultiCampaign,
+      'Plan campaign mismatch template - different campaign',
+      'PROOF_APPROVED',
+      {
+        letterVariantId: 'variant',
+        longFormRender: { status: 'RENDERED' },
+        shortFormRender: { status: 'RENDERED' },
+        campaignId: 'other-campaign-id',
+      }
+    );
+
+    await storageHelper.seed([dbEntry]);
+    await templateStorageHelper.seedTemplateData([
+      letterTemplate1,
+      letterTemplate2,
+    ]);
+
+    const update = {
+      cascade: [
+        {
+          cascadeGroups: ['standard'],
+          channel: 'LETTER',
+          channelType: 'primary',
+          defaultTemplateId: letterTemplate1.id,
+        },
+        {
+          cascadeGroups: ['standard'],
+          channel: 'LETTER',
+          channelType: 'secondary',
+          defaultTemplateId: letterTemplate2.id,
+        },
+      ],
+      cascadeGroupOverrides: [],
+    };
+
+    const updateResponse = await request.patch(
+      `${process.env.API_BASE_URL}/v1/routing-configuration/${dbEntry.id}`,
+      {
+        headers: {
+          Authorization: await userMultiCampaign.getAccessToken(),
+          'X-Lock-Number': String(dbEntry.lockNumber),
+        },
+        data: update,
+      }
+    );
+
+    expect(updateResponse.status()).toBe(400);
+
+    const updated = await updateResponse.json();
+
+    expect(updated).toEqual({
+      statusCode: 400,
+      technicalMessage: 'Some templates failed validation',
+      details: {
+        templateIds: letterTemplate2.id,
+      },
+    });
+  });
 });
diff --git a/tests/test-team/template-mgmt-routing-component-tests/letter/preview-british-sign-language-letter-template.routing-component.spec.ts b/tests/test-team/template-mgmt-routing-component-tests/letter/preview-british-sign-language-letter-template.routing-component.spec.ts
index ec8ea410d..e68276678 100644
--- a/tests/test-team/template-mgmt-routing-component-tests/letter/preview-british-sign-language-letter-template.routing-component.spec.ts
+++ b/tests/test-team/template-mgmt-routing-component-tests/letter/preview-british-sign-language-letter-template.routing-component.spec.ts
@@ -78,6 +78,7 @@ function createTemplates(user: TestUser, letterVariant: LetterVariant) {
         letterType: 'q4',
         shortFormRender: { status: 'RENDERED' },
         longFormRender: { status: 'RENDERED' },
+        letterVariantId: letterVariant.id,
       }
     ),
   };