Staffordshire Building Society is setting up a subsidiary to help borrowers who do not fit its normal lending criteria.
The service will give customers access to a panel of alternative lenders.
The society is training branch staff to become mortgage advisers with Staffordshire Lending Services, which will start doing business in May.
It is talking to a number of lenders about joining the panel.
Staffordshire says it is being forced to turn away potential borrowers looking for 100 per cent mortgages or wanting higher income multiples. It also hopes to sell them its own products, including savings and current accounts.
It is the latest society to create or buy a subsidiary for non-standard mortgage business.
Head of marketing Richard Dickson says: “We will no longer have to say to some people who come into our branches: 'Sorry, we can't help you.' “Advisers will be able to introduce to other lenders as well as advise on our own mortgages.”