If your bank/building society has not responded adequately, or in time, to a complaint that you have already made, you can register your complaint with the Financial Ombudsman Service. Which offers a guide on consumer rights when taking a complaint to the Financial Ombudsman Service.
The Banking Standards Board (BSB) was created to help promote high standards of ethical behaviour and competence across the UK’s banks and building societies. The BSB does not have statutory powers and is unable to deal with customer or staff complaints.
If you have had a complaint about your bank or building society, we would recommend that you contact them, in the first instance, about the problem. You should usually expect to receive a response within eight weeks.