diff --git a/app/models.py b/app/models.py
index de42129f0..378c45b3e 100644
--- a/app/models.py
+++ b/app/models.py
@@ -10,7 +10,7 @@ from sqlalchemy.dialects.postgresql import (
     JSON
 )
 from sqlalchemy import UniqueConstraint, and_
-from sqlalchemy.orm import backref, foreign, remote
+from sqlalchemy.orm import foreign, remote
 from notifications_utils.recipients import (
     validate_email_address,
     validate_phone_number,
@@ -223,11 +223,10 @@ class ServicePermission(db.Model):
                            primary_key=True, index=True, nullable=False)
     permission = db.Column(db.String(255), db.ForeignKey('service_permission_types.name'),
                            index=True, primary_key=True, nullable=False)
-    service = db.relationship("Service", foreign_keys=[service_id])
+    service = db.relationship("Service")
     created_at = db.Column(db.DateTime, default=datetime.datetime.utcnow, nullable=False)
 
-    service_permission_types = db.relationship(
-        Service, backref=backref("permissions", cascade="all, delete-orphan"))
+    service_permission_types = db.relationship(Service, backref=db.backref("permissions"))
 
     def __repr__(self):
         return '<{} has service permission: {}>'.format(self.service_id, self.permission)
diff --git a/migrations/versions/0085_update_incoming_to_inbound.py b/migrations/versions/0085_update_incoming_to_inbound.py
index e5d15f064..ae4388c27 100644
--- a/migrations/versions/0085_update_incoming_to_inbound.py
+++ b/migrations/versions/0085_update_incoming_to_inbound.py
@@ -15,14 +15,10 @@ import sqlalchemy as sa
 from sqlalchemy.dialects import postgresql
 
 def upgrade():
-    # ### commands auto generated by Alembic - please adjust! ###
     op.drop_column('service_permissions', 'updated_at')
     op.execute("UPDATE service_permission_types SET name='inbound_sms' WHERE name='incoming_sms'")
-    # ### end Alembic commands ###
 
 
 def downgrade():
-    # ### commands auto generated by Alembic - please adjust! ###
     op.add_column('service_permissions', sa.Column('updated_at', postgresql.TIMESTAMP(), autoincrement=False, nullable=True))
     op.execute("UPDATE service_permission_types SET name='incoming_sms' WHERE name='inbound_sms'")
-    # ### end Alembic commands ###
diff --git a/tests/app/dao/test_services_dao.py b/tests/app/dao/test_services_dao.py
index 2dc6f199f..0a682ad54 100644
--- a/tests/app/dao/test_services_dao.py
+++ b/tests/app/dao/test_services_dao.py
@@ -44,6 +44,8 @@ from app.models import (
     User,
     InvitedUser,
     Service,
+    ServicePermission,
+    ServicePermissionTypes,
     BRANDING_GOVUK,
     DVLA_ORG_HM_GOVERNMENT,
     KEY_TYPE_NORMAL,
@@ -52,7 +54,8 @@ from app.models import (
     EMAIL_TYPE,
     SMS_TYPE,
     LETTER_TYPE,
-    INTERNATIONAL_SMS_TYPE
+    INTERNATIONAL_SMS_TYPE,
+    SERVICE_PERMISSION_TYPES
 )
 
 from tests.app.db import create_user, create_service
@@ -286,6 +289,14 @@ def test_remove_permission_from_service_by_id_returns_service_with_correct_permi
     assert service.permissions[0].permission == EMAIL_TYPE
 
 
+def test_remove_service_does_not_remove_service_permission_types(sample_service):
+    delete_service_and_all_associated_db_objects(sample_service)
+
+    services = dao_fetch_all_services()
+    assert len(services) == 0
+    assert set([p.name for p in ServicePermissionTypes.query.all()]) == set(SERVICE_PERMISSION_TYPES)
+
+
 def test_create_service_by_id_adding_and_removing_letter_returns_service_without_letter(service_factory):
     service = service_factory.get('testing', email_from='testing')
 
@@ -392,6 +403,9 @@ def test_delete_service_and_associated_objects(notify_db,
                                                sample_invited_user,
                                                sample_permission,
                                                sample_provider_statistics):
+    # Default service permissions of Email and SMS
+    assert ServicePermission.query.count() == 2
+
     delete_service_and_all_associated_db_objects(sample_service)
     assert NotificationStatistics.query.count() == 0
     assert TemplateStatistics.query.count() == 0
@@ -408,6 +422,7 @@ def test_delete_service_and_associated_objects(notify_db,
     assert InvitedUser.query.count() == 0
     assert Service.query.count() == 0
     assert Service.get_history_model().query.count() == 0
+    assert ServicePermission.query.count() == 0
 
 
 def test_add_existing_user_to_another_service_doesnot_change_old_permissions(sample_user):