diff --git a/app/models.py b/app/models.py
index 485edf944..d6018d98c 100644
--- a/app/models.py
+++ b/app/models.py
@@ -337,7 +337,7 @@ class ServiceSmsSender(db.Model):
 
     id = db.Column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
     sms_sender = db.Column(db.String(11), nullable=False)
-    service_id = db.Column(UUID(as_uuid=True), db.ForeignKey('services.id'), index=True, nullable=False)
+    service_id = db.Column(UUID(as_uuid=True), db.ForeignKey('services.id'), index=True, nullable=False, unique=False)
     service = db.relationship(Service, backref=db.backref("service_sms_senders", uselist=True))
     is_default = db.Column(db.Boolean, nullable=False, default=True)
     inbound_number_id = db.Column(UUID(as_uuid=True), db.ForeignKey('inbound_numbers.id'),
@@ -894,7 +894,7 @@ DVLA_RESPONSE_STATUS_SENT = 'Sent'
 class NotificationStatusTypes(db.Model):
     __tablename__ = 'notification_status_types'
 
-    name = db.Column(db.String(255), primary_key=True)
+    name = db.Column(db.String(), primary_key=True)
 
 
 class Notification(db.Model):
@@ -1520,3 +1520,24 @@ class NotificationEmailReplyTo(db.Model):
         nullable=False,
         primary_key=True
     )
+
+
+class NotificationSmsSender(db.Model):
+    __tablename__ = "notification_to_sms_sender"
+
+    notification_id = db.Column(
+        UUID(as_uuid=True),
+        db.ForeignKey('notifications.id'),
+        unique=True,
+        index=True,
+        nullable=False,
+        primary_key=True
+    )
+    service_sms_sender_id = db.Column(
+        UUID(as_uuid=True),
+        db.ForeignKey('service_sms_senders.id'),
+        unique=False,
+        index=True,
+        nullable=False,
+        primary_key=True
+    )
diff --git a/migrations/versions/0128_noti_to_sms_sender.py b/migrations/versions/0128_noti_to_sms_sender.py
new file mode 100644
index 000000000..75ca2f14e
--- /dev/null
+++ b/migrations/versions/0128_noti_to_sms_sender.py
@@ -0,0 +1,44 @@
+"""
+
+Revision ID: 0128_noti_to_sms_sender
+Revises: 0127_remove_unique_constraint
+Create Date: 2017-10-26 15:17:00.752706
+
+"""
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+revision = '0128_noti_to_sms_sender'
+down_revision = '0127_remove_unique_constraint'
+
+
+def upgrade():
+    op.create_index(op.f('ix_service_letter_contacts_service_id'), 'service_letter_contacts', ['service_id'],
+                    unique=False)
+    op.drop_index('ix_service_letter_contact_service_id', table_name='service_letter_contacts')
+    op.create_index(op.f('ix_service_sms_senders_service_id'), 'service_sms_senders', ['service_id'], unique=False)
+    op.execute(
+        'ALTER TABLE templates_history ALTER COLUMN template_type TYPE template_type USING template_type::template_type')
+
+    # new table
+    op.create_table('notification_to_sms_sender',
+    sa.Column('notification_id', postgresql.UUID(as_uuid=True), nullable=False),
+    sa.Column('service_sms_sender_id', postgresql.UUID(as_uuid=True), nullable=False),
+    sa.ForeignKeyConstraint(['notification_id'], ['notifications.id'], ),
+    sa.ForeignKeyConstraint(['service_sms_sender_id'], ['service_sms_senders.id'], ),
+    sa.PrimaryKeyConstraint('notification_id', 'service_sms_sender_id')
+    )
+    op.create_index(op.f('ix_notification_to_sms_sender_notification_id'), 'notification_to_sms_sender', ['notification_id'], unique=True)
+    op.create_index(op.f('ix_notification_to_sms_sender_service_sms_sender_id'), 'notification_to_sms_sender', ['service_sms_sender_id'], unique=False)
+
+
+def downgrade():
+    op.drop_index(op.f('ix_service_sms_senders_service_id'), table_name='service_sms_senders')
+    op.create_index('ix_service_letter_contact_service_id', 'service_letter_contacts', ['service_id'], unique=False)
+    op.drop_index(op.f('ix_service_letter_contacts_service_id'), table_name='service_letter_contacts')
+    op.alter_column('templates_history', 'template_type',
+                    type_=sa.VARCHAR(),
+                    existing_nullable=False)
+
+    op.drop_table('notification_to_sms_sender')