diff --git a/app/dao/notifications_dao.py b/app/dao/notifications_dao.py
index 22fdb4257..89526260a 100644
--- a/app/dao/notifications_dao.py
+++ b/app/dao/notifications_dao.py
@@ -334,7 +334,7 @@ def delete_notifications_created_more_than_a_week_ago_by_type(notification_type)
                                                       services_with_data_retention))
     if notification_type == LETTER_TYPE:
         _delete_letters_from_s3(query=query)
-    deleted = query.delete(synchronize_session='fetch')
+    deleted += query.delete(synchronize_session='fetch')
     return deleted
 
 
@@ -342,19 +342,20 @@ def _delete_letters_from_s3(query):
     letters_to_delete_from_s3 = query.all()
     for letter in letters_to_delete_from_s3:
         bucket_name = current_app.config['LETTERS_PDF_BUCKET_NAME']
-        sent_at = str(letter.sent_at.date())
-        prefix = LETTERS_PDF_FILE_LOCATION_STRUCTURE.format(
-            folder=sent_at,
-            reference=letter.reference,
-            duplex="D",
-            letter_class="2",
-            colour="C",
-            crown="C" if letter.service.crown else "N",
-            date=''
-        ).upper()[:-5]
-        s3_objects = get_s3_bucket_objects(bucket_name=bucket_name, subfolder=prefix)
-        for s3_object in s3_objects:
-            remove_s3_object(bucket_name, s3_object['Key'])
+        if letter.sent_at:
+            sent_at = str(letter.sent_at.date())
+            prefix = LETTERS_PDF_FILE_LOCATION_STRUCTURE.format(
+                folder=sent_at,
+                reference=letter.reference,
+                duplex="D",
+                letter_class="2",
+                colour="C",
+                crown="C" if letter.service.crown else "N",
+                date=''
+            ).upper()[:-5]
+            s3_objects = get_s3_bucket_objects(bucket_name=bucket_name, subfolder=prefix)
+            for s3_object in s3_objects:
+                remove_s3_object(bucket_name, s3_object['Key'])
 
 
 @statsd(namespace="dao")
diff --git a/tests/app/dao/notification_dao/test_notification_dao_delete_notifications.py b/tests/app/dao/notification_dao/test_notification_dao_delete_notifications.py
index 8284947ca..55ef4a659 100644
--- a/tests/app/dao/notification_dao/test_notification_dao_delete_notifications.py
+++ b/tests/app/dao/notification_dao/test_notification_dao_delete_notifications.py
@@ -176,6 +176,16 @@ def test_delete_notifications_delete_notification_type_for_default_time_if_no_da
     assert len(Notification.query.filter_by(notification_type='email').all()) == 1
 
 
+def test_delete_notifications_does_try_to_delete_from_s3_when_letter_has_not_been_sent(sample_service, mocker):
+    mock_get_s3 = mocker.patch("app.dao.notifications_dao.get_s3_bucket_objects")
+    letter_template = create_template(service=sample_service, template_type='letter')
+
+    create_notification(template=letter_template, status='sending',
+                        reference='LETTER_REF')
+    delete_notifications_created_more_than_a_week_ago_by_type('email')
+    mock_get_s3.assert_not_called()
+
+
 def _create_templates(sample_service):
     email_template = create_template(service=sample_service, template_type='email')
     sms_template = create_template(service=sample_service)