diff --git a/app/main/views/invites.py b/app/main/views/invites.py
index 3d9544b8e..3f5004523 100644
--- a/app/main/views/invites.py
+++ b/app/main/views/invites.py
@@ -27,10 +27,10 @@ def accept_invite(token):
         flash("""
             You’re signed in as {}.
             This invite is for another email address.
-            <a href='{}'>Sign out</a> and click the link again to accept this invite.
+            {} and click the link again to accept this invite.
         """.format(
             current_user.email_address,
-            url_for("main.sign_out")
+            url_for("main.sign_out", _external=True)
         ))
         abort(403)
 
diff --git a/tests/app/main/views/test_accept_invite.py b/tests/app/main/views/test_accept_invite.py
index d81fd6d28..6784bee50 100644
--- a/tests/app/main/views/test_accept_invite.py
+++ b/tests/app/main/views/test_accept_invite.py
@@ -287,7 +287,8 @@ def test_signed_in_existing_user_cannot_use_anothers_invite(app_,
             banner_contents = flash_banners[0].text.strip()
             assert "You’re signed in as test@user.gov.uk." in banner_contents
             assert "This invite is for another email address." in banner_contents
-            assert "<a href='/sign-out'>Sign out</a> and click the link again to accept this invite." in banner_contents
+            assert "{} and click the link again to accept this invite.".format(
+                url_for("main.sign_out", _external=True)) in banner_contents
             assert mock_accept_invite.call_count == 0