diff --git a/frontend/src/__tests__/app/message-plans/create-message-plan/page.test.tsx b/frontend/src/__tests__/app/message-plans/create-message-plan/page.test.tsx
index 69c7f7490..76c017989 100644
--- a/frontend/src/__tests__/app/message-plans/create-message-plan/page.test.tsx
+++ b/frontend/src/__tests__/app/message-plans/create-message-plan/page.test.tsx
@@ -68,8 +68,6 @@ describe('CreateMessagePlanPage', () => {
 
     await user.click(screen.getByTestId('submit-button'));
 
-    expect(container.asFragment()).toMatchSnapshot();
-
     expect(createMessagePlanServerAction).toHaveBeenCalledTimes(1);
     expect(createMessagePlanServerAction).toHaveBeenCalledWith(
       {},
@@ -86,13 +84,14 @@ describe('CreateMessagePlanPage', () => {
       name: 'My Message Plan',
     });
 
-    const errorSummaryHeading = await screen.getByTestId('error-summary');
-
-    // "error-summary" test id targets the nested heading rather than the top level of the error summary
+    //  error-summary" test id targets the nested heading rather than the top level of the error summary
     // so we need to assert against the parent element
-    await waitFor(() => {
+    await waitFor(async () => {
+      const errorSummaryHeading = await screen.getByTestId('error-summary');
       expect(errorSummaryHeading.parentElement).toHaveFocus();
     });
+
+    expect(container.asFragment()).toMatchSnapshot();
   });
 
   test('redirects when there are no campaignIds', async () => {
diff --git a/frontend/src/__tests__/components/organisms/PreviewLetterTemplate.test.tsx b/frontend/src/__tests__/components/organisms/PreviewLetterTemplate.test.tsx
index 34c202b9c..17e4b6aba 100644
--- a/frontend/src/__tests__/components/organisms/PreviewLetterTemplate.test.tsx
+++ b/frontend/src/__tests__/components/organisms/PreviewLetterTemplate.test.tsx
@@ -1,8 +1,10 @@
 import { PreviewLetterTemplate } from '@organisms/PreviewLetterTemplate/PreviewLetterTemplate';
 import { render } from '@testing-library/react';
 import { isRightToLeft } from 'nhs-notify-web-template-management-utils/enum';
+import { useFeatureFlags } from '@providers/client-config-provider';
 
 jest.mock('nhs-notify-web-template-management-utils/enum');
+jest.mock('@providers/client-config-provider');
 
 const isRightToLeftMock = jest.mocked(isRightToLeft);
 
@@ -10,6 +12,7 @@ describe('PreviewLetterTemplate component', () => {
   beforeEach(() => {
     jest.resetAllMocks();
     isRightToLeftMock.mockReturnValueOnce(false);
+    jest.mocked(useFeatureFlags).mockReturnValue({ routing: false });
   });
 
   it('matches snapshot when template status is VIRUS_SCAN_FAILED', () => {
@@ -129,6 +132,42 @@ describe('PreviewLetterTemplate component', () => {
     expect(container.asFragment()).toMatchSnapshot();
   });
 
+  it('matches snapshot when template status is PROOF_AVAILABLE and routing flag is enabled', () => {
+    jest.mocked(useFeatureFlags).mockReturnValue({ routing: true });
+    const container = render(
+      <PreviewLetterTemplate
+        template={{
+          id: '2C56C5F6-B3AD-4FF8-A8A2-52E4FA8AF2BE',
+          clientId: 'client-id',
+          name: 'letter',
+          templateType: 'LETTER',
+          templateStatus: 'PROOF_AVAILABLE',
+          letterType: 'x1',
+          language: 'en',
+          files: {
+            pdfTemplate: {
+              fileName: 'file.pdf',
+              currentVersion: 'b',
+              virusScanStatus: 'PASSED',
+            },
+            proofs: {
+              'your-proof.pdf': {
+                fileName: 'your-proof.pdf',
+                virusScanStatus: 'PASSED',
+                supplier: 'MBA',
+              },
+            },
+          },
+          proofingEnabled: true,
+          createdAt: '2025-04-02T09:33:25.729Z',
+          updatedAt: '2025-04-02T09:33:25.729Z',
+        }}
+      />
+    );
+
+    expect(container.asFragment()).toMatchSnapshot();
+  });
+
   it('matches snapshot when template status is NOT_YET_SUBMITTED', () => {
     const container = render(
       <PreviewLetterTemplate
diff --git a/frontend/src/__tests__/components/organisms/__snapshots__/PreviewLetterTemplate.test.tsx.snap b/frontend/src/__tests__/components/organisms/__snapshots__/PreviewLetterTemplate.test.tsx.snap
index 84b5b688d..53237a5d6 100644
--- a/frontend/src/__tests__/components/organisms/__snapshots__/PreviewLetterTemplate.test.tsx.snap
+++ b/frontend/src/__tests__/components/organisms/__snapshots__/PreviewLetterTemplate.test.tsx.snap
@@ -1004,6 +1004,260 @@ exports[`PreviewLetterTemplate component matches snapshot when template status i
 </DocumentFragment>
 `;
 
+exports[`PreviewLetterTemplate component matches snapshot when template status is PROOF_AVAILABLE and routing flag is enabled 1`] = `
+<DocumentFragment>
+  <a
+    class="nhsuk-back-link"
+    href="/message-templates"
+  >
+    Back to all templates
+  </a>
+  <main
+    class="nhsuk-main-wrapper"
+    id="maincontent"
+    role="main"
+  >
+    <div
+      class="nhsuk-grid-row"
+    >
+      <div
+        class="nhsuk-grid-column-full"
+      >
+        <div
+          class="nhsuk-u-reading-width"
+        >
+          <span
+            class="nhsuk-caption-l"
+          >
+            Template
+          </span>
+          <h1
+            class="preview__heading"
+            data-testid="preview-message__heading"
+          >
+            letter
+          </h1>
+        </div>
+        <div
+          class="nhsuk-width-container nhsuk-u-margin-bottom-6 nhsuk-body-m"
+        >
+          <dl
+            class="nhsuk-summary-list nhsuk-u-margin-bottom-4 preview"
+          >
+            <div
+              class="nhsuk-summary-list__row"
+            >
+              <dt
+                class="nhsuk-summary-list__key"
+              >
+                Template ID
+              </dt>
+              <dd
+                class="nhsuk-summary-list__value"
+              >
+                2C56C5F6-B3AD-4FF8-A8A2-52E4FA8AF2BE
+              </dd>
+            </div>
+            <div
+              class="nhsuk-summary-list__row"
+            >
+              <dt
+                class="nhsuk-summary-list__key"
+              >
+                Type
+              </dt>
+              <dd
+                class="nhsuk-summary-list__value"
+              />
+            </div>
+            <div
+              class="nhsuk-summary-list__row"
+            >
+              <dt
+                class="nhsuk-summary-list__key"
+              >
+                Status
+              </dt>
+              <dd
+                class="nhsuk-summary-list__value"
+              >
+                <strong
+                  class="nhsuk-tag"
+                  data-test-id="status-tag-proof-available"
+                />
+              </dd>
+            </div>
+            <div
+              class="nhsuk-summary-list__row"
+            >
+              <dt
+                class="nhsuk-summary-list__key"
+              >
+                Template file
+              </dt>
+              <dd
+                class="nhsuk-summary-list__value"
+              >
+                <div
+                  class="container"
+                >
+                  <svg
+                    aria-hidden="true"
+                    class="icon"
+                    fill="none"
+                    height="26"
+                    viewBox="0 0 20 26"
+                    width="20"
+                    xmlns="http://www.w3.org/2000/svg"
+                  >
+                    <path
+                      d="M0 0V26H20V6.59375L19.7188 6.28125L13.7188 0.28125L13.4062 0H0ZM2 2H12V8H18V24H2V2ZM14 3.4375L16.5625 6H14V3.4375Z"
+                      fill="#4C6272"
+                    />
+                  </svg>
+                  <p
+                    class="text"
+                  >
+                    file.pdf
+                  </p>
+                </div>
+              </dd>
+            </div>
+          </dl>
+          <dl
+            class="nhsuk-summary-list nhsuk-u-margin-bottom-4 preview"
+          >
+            <div
+              class="nhsuk-summary-list__row"
+            >
+              <dt
+                class="nhsuk-summary-list__key"
+              >
+                Template proof files
+              </dt>
+              <dd
+                class="nhsuk-summary-list__value"
+              >
+                <ul
+                  class="proofs"
+                >
+                  <li>
+                    <a
+                      data-testid="proof-link_your-proof.pdf"
+                      href="/templates/files/client-id/proofs/2C56C5F6-B3AD-4FF8-A8A2-52E4FA8AF2BE/your-proof.pdf"
+                      rel="noopener noreferrer"
+                      target="_blank"
+                    >
+                      <div
+                        class="container"
+                      >
+                        <svg
+                          aria-hidden="true"
+                          class="icon"
+                          fill="none"
+                          height="26"
+                          viewBox="0 0 20 26"
+                          width="20"
+                          xmlns="http://www.w3.org/2000/svg"
+                        >
+                          <path
+                            d="M0 0V26H20V6.59375L19.7188 6.28125L13.7188 0.28125L13.4062 0H0ZM2 2H12V8H18V24H2V2ZM14 3.4375L16.5625 6H14V3.4375Z"
+                            fill="#4C6272"
+                          />
+                        </svg>
+                        <p
+                          class="text"
+                        >
+                          your-proof.pdf
+                        </p>
+                      </div>
+                    </a>
+                  </li>
+                </ul>
+              </dd>
+            </div>
+          </dl>
+        </div>
+        <section
+          class="nhsuk-u-reading-width"
+        >
+          <details
+            class="nhsuk-details"
+          >
+            <summary
+              class="nhsuk-details__summary"
+            >
+              <span
+                class="nhsuk-details__summary-text"
+              >
+                If this proof does not match the template
+              </span>
+            </summary>
+            <div
+              class="nhsuk-details__text"
+            >
+              <p>
+                If the content or formatting of your template proof does not match the template you originally provided, contact us to describe what's wrong with the template proof.
+              </p>
+              <p>
+                We'll update the template proof and email it to you.
+              </p>
+              <p>
+                It can take 5 to 10 working days to get another proof of your template.
+              </p>
+              <p>
+                If any personalisation does not appear how you expect, you may need to check if you're using the correct personalisation fields or if your example data is correct.
+              </p>
+            </div>
+          </details>
+          <details
+            class="nhsuk-details"
+          >
+            <summary
+              class="nhsuk-details__summary"
+            >
+              <span
+                class="nhsuk-details__summary-text"
+              >
+                If you need to edit the template
+              </span>
+            </summary>
+            <div
+              class="nhsuk-details__text"
+            >
+              <p>
+                Edit your original template on your computer, convert it to PDF and then upload as a new template.
+              </p>
+            </div>
+          </details>
+          <p>
+            If you're happy with this template proof, approve it. Then your template will be ready to add to a message plan.
+          </p>
+        </section>
+        <a
+          aria-disabled="false"
+          class="nhsuk-button"
+          data-testid="preview-letter-template-cta"
+          draggable="false"
+          href="/templates/submit-letter-template/2C56C5F6-B3AD-4FF8-A8A2-52E4FA8AF2BE"
+          id="preview-letter-template-cta"
+          role="button"
+        >
+          Approve template proof
+        </a>
+        <p>
+          <a
+            href="/message-templates"
+          >
+            Back to all templates
+          </a>
+        </p>
+      </div>
+    </div>
+  </main>
+</DocumentFragment>
+`;
+
 exports[`PreviewLetterTemplate component matches snapshot when template status is VALIDATION_FAILED 1`] = `
 <DocumentFragment>
   <a
diff --git a/frontend/src/components/organisms/PreviewLetterTemplate/PreviewLetterTemplate.tsx b/frontend/src/components/organisms/PreviewLetterTemplate/PreviewLetterTemplate.tsx
index 6e3eebf54..cbf901767 100644
--- a/frontend/src/components/organisms/PreviewLetterTemplate/PreviewLetterTemplate.tsx
+++ b/frontend/src/components/organisms/PreviewLetterTemplate/PreviewLetterTemplate.tsx
@@ -13,6 +13,7 @@ import { TemplateStatus } from 'nhs-notify-backend-client';
 import classNames from 'classnames';
 import { NhsNotifyErrorSummary } from '@molecules/NhsNotifyErrorSummary/NhsNotifyErrorSummary';
 import NotifyBackLink from '@atoms/NHSNotifyBackLink/NHSNotifyBackLink';
+import { useFeatureFlags } from '@providers/client-config-provider';
 
 type ButtonDetails = { text: string; href: string };
 
@@ -20,6 +21,7 @@ export function PreviewLetterTemplate({
   template,
 }: Readonly<{ template: LetterTemplate }>) {
   const {
+    approveProofText,
     backLinkText,
     footer,
     preSubmissionText,
@@ -33,6 +35,7 @@ export function PreviewLetterTemplate({
   } = content.components.previewLetterTemplate;
 
   const basePath = getBasePath();
+  const { routing } = useFeatureFlags();
 
   const buttonMap: Record<string, ButtonDetails> = {
     NOT_YET_SUBMITTED: {
@@ -40,7 +43,7 @@ export function PreviewLetterTemplate({
       href: `${basePath}/submit-letter-template/${template.id}`,
     },
     PROOF_AVAILABLE: {
-      text: submitText,
+      text: routing ? approveProofText : submitText,
       href: `${basePath}/submit-letter-template/${template.id}`,
     },
     PENDING_PROOF_REQUEST: {
@@ -86,11 +89,12 @@ export function PreviewLetterTemplate({
                     {preSubmissionText.ifDoesNotMatch.summary}
                   </Details.Summary>
                   <Details.Text>
-                    {preSubmissionText.ifDoesNotMatch.paragraphs.map(
-                      (text, i) => (
-                        <p key={i}>{text}</p>
-                      )
-                    )}
+                    {(routing
+                      ? preSubmissionText.ifDoesNotMatch.paragraphsApproval
+                      : preSubmissionText.ifDoesNotMatch.paragraphsSubmit
+                    ).map((text, i) => (
+                      <p key={i}>{text}</p>
+                    ))}
                   </Details.Text>
                 </Details>
                 <Details>
@@ -101,7 +105,11 @@ export function PreviewLetterTemplate({
                     <p>{preSubmissionText.ifNeedsEdit.paragraph}</p>
                   </Details.Text>
                 </Details>
-                <p>{preSubmissionText.ifYouAreHappyParagraph}</p>
+                <p>
+                  {routing
+                    ? preSubmissionText.ifYouAreHappyParagraphApproval
+                    : preSubmissionText.ifYouAreHappyParagraphSubmit}
+                </p>
               </section>
             ) : null}
 
diff --git a/frontend/src/content/content.ts b/frontend/src/content/content.ts
index a66048e68..36dd8bf71 100644
--- a/frontend/src/content/content.ts
+++ b/frontend/src/content/content.ts
@@ -484,26 +484,35 @@ const previewLetterFooter: Partial<Record<TemplateStatus, string[]>> = {
 const previewLetterPreSubmissionText = {
   ifDoesNotMatch: {
     summary: 'If this proof does not match the template',
-    paragraphs: [
+    paragraphsSubmit: [
       "If the content or formatting of your proof does not match the template you originally provided, contact NHS Notify to describe what's wrong with the proof.",
       'NHS Notify will make the relevant changes and reproof your template.',
       'It can take 5 to 10 working days to get another proof of your template.',
       "If any personalisation does not appear how you expect, you may need to check if you're using the correct personalisation fields or if your example data is correct.",
     ],
+    paragraphsApproval: [
+      "If the content or formatting of your template proof does not match the template you originally provided, contact us to describe what's wrong with the template proof.",
+      "We'll update the template proof and email it to you.",
+      'It can take 5 to 10 working days to get another proof of your template.',
+      "If any personalisation does not appear how you expect, you may need to check if you're using the correct personalisation fields or if your example data is correct.",
+    ],
   },
   ifNeedsEdit: {
     summary: 'If you need to edit the template',
     paragraph:
       'Edit your original template on your computer, convert it to PDF and then upload as a new template.',
   },
-  ifYouAreHappyParagraph:
+  ifYouAreHappyParagraphSubmit:
     "If you're happy with this proof, submit the template and NHS Notify will use it to set up the messages you want to send.",
+  ifYouAreHappyParagraphApproval:
+    "If you're happy with this template proof, approve it. Then your template will be ready to add to a message plan.",
 };
 
 const previewLetterTemplate = {
   pageTitle: generatePageTitle('Preview letter template'),
   backLinkText: backToAllTemplates,
   submitText: 'Submit template',
+  approveProofText: 'Approve template proof',
   requestProofText: 'Request a proof',
   footer: previewLetterFooter,
   virusScanError: 'The file(s) you uploaded may contain a virus.',