diff --git a/app/delivery/send_to_providers.py b/app/delivery/send_to_providers.py
index 23d7f4f0e..e761956f3 100644
--- a/app/delivery/send_to_providers.py
+++ b/app/delivery/send_to_providers.py
@@ -171,7 +171,12 @@ def provider_to_use(notification_type, international=False):
         )
         raise Exception("No active {} providers".format(notification_type))
 
-    chosen_provider = random.choices(active_providers, weights=[p.priority for p in active_providers])[0]
+    if len(active_providers) == 1:
+        weights = [100]
+    else:
+        weights = [p.priority for p in active_providers]
+
+    chosen_provider = random.choices(active_providers, weights=weights)[0]
 
     return notification_provider_clients.get_client_by_name_and_type(chosen_provider.identifier, notification_type)
 
diff --git a/tests/app/delivery/test_send_to_providers.py b/tests/app/delivery/test_send_to_providers.py
index 16e8a817c..cf1ef1552 100644
--- a/tests/app/delivery/test_send_to_providers.py
+++ b/tests/app/delivery/test_send_to_providers.py
@@ -72,8 +72,18 @@ def test_provider_to_use_should_cache_repeated_calls(mocker, notify_db_session):
     assert len(mock_choices.call_args_list) == 1
 
 
-def test_provider_to_use_should_only_return_mmg_for_international(mocker, notify_db_session):
+@pytest.mark.parametrize('international_provider_priority', (
+    # Since there’s only one international provider it should always
+    # be used, no matter what its priority is set to
+    0, 50, 100,
+))
+def test_provider_to_use_should_only_return_mmg_for_international(
+    mocker,
+    notify_db_session,
+    international_provider_priority,
+):
     mmg = get_provider_details_by_identifier('mmg')
+    mmg.priority = international_provider_priority
     mock_choices = mocker.patch('app.delivery.send_to_providers.random.choices', return_value=[mmg])
 
     ret = send_to_providers.provider_to_use('sms', international=True)
@@ -90,7 +100,7 @@ def test_provider_to_use_should_only_return_active_providers(mocker, restore_pro
 
     ret = send_to_providers.provider_to_use('sms')
 
-    mock_choices.assert_called_once_with([firetext], weights=[0])
+    mock_choices.assert_called_once_with([firetext], weights=[100])
     assert ret.get_name() == 'firetext'