diff --git a/app/main/forms.py b/app/main/forms.py
index 643fdcd31..f5929ee80 100644
--- a/app/main/forms.py
+++ b/app/main/forms.py
@@ -1,6 +1,7 @@
 import weakref
 from datetime import datetime, timedelta
 from itertools import chain
+from operator import itemgetter
 
 import pytz
 from flask_wtf import FlaskForm as Form
@@ -785,7 +786,10 @@ class LetterBranding(StripWhitespaceForm):
 
     def __init__(self, choices=[], *args, **kwargs):
         super().__init__(*args, **kwargs)
-        self.dvla_org_id.choices = choices
+        self.dvla_org_id.choices = list(sorted(
+            choices,
+            key=itemgetter(1),
+        ))
 
     dvla_org_id = RadioField(
         'Which logo should this service’s letter have?',
diff --git a/tests/app/main/views/test_service_settings.py b/tests/app/main/views/test_service_settings.py
index 27c038082..e7f36b77f 100644
--- a/tests/app/main/views/test_service_settings.py
+++ b/tests/app/main/views/test_service_settings.py
@@ -2088,6 +2088,7 @@ def test_set_letter_branding_platform_admin_only(
 @pytest.mark.parametrize('current_dvla_org_id, expected_selected', [
     (None, '001'),
     ('500', '500'),
+    ('999', '999'),
 ])
 def test_set_letter_branding_prepopulates(
     logged_in_platform_admin_client,
@@ -2101,6 +2102,20 @@ def test_set_letter_branding_prepopulates(
     response = logged_in_platform_admin_client.get(url_for('main.set_letter_branding', service_id=service_one['id']))
     assert response.status_code == 200
     page = BeautifulSoup(response.data.decode('utf-8'), 'html.parser')
+
+    for element in {'label', 'input[type=radio]'}:
+        assert len(page.select(element)) == 3
+
+    assert normalize_spaces(page.select('label')[0].text) == 'Animal and Plant Health Agency'
+    assert page.select('input')[0]['value'] == '999'
+
+    assert normalize_spaces(page.select('label')[1].text) == 'HM Government'
+    assert page.select('input')[1]['value'] == '001'
+
+    assert normalize_spaces(page.select('label')[2].text) == 'Land Registry'
+    assert page.select('input')[2]['value'] == '500'
+
+    assert len(page.select('input[checked]')) == 1
     assert page.select('input[checked]')[0]['value'] == expected_selected
 
 
diff --git a/tests/conftest.py b/tests/conftest.py
index 0b7c18c3f..4517203f9 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -2492,6 +2492,7 @@ def mock_get_letter_email_branding(mocker):
         return {
             '001': 'HM Government',
             '500': 'Land Registry',
+            '999': 'Animal and Plant Health Agency',
         }
 
     return mocker.patch(