An estimated one in four Britons would be turned down by a mainstream mortgage lender.

This is because not everyone fits the standard criteria lenders apply. But don't worry if you are one such customer - help is at hand.

These days there are around a dozen 'non-standard sub prime' mortgage lenders, who cater for individual cases. Some of them are standalone, others are owned by mainstream banks and building societies. All of them offer viable mortgage alternatives for those prospective borrowers who may not fit the standard mould. 'Non-standard sub prime' can cover a range of different borrower types.

If you have a less-than-perfect credit record, if your requirements are out of the ordinary or if you are self-employed you may fall into this category. If you have never had a bank account or if you have lived at lots of different addresses some lenders will not want you as a customer. As 'non-standard sub prime' mortgage borrowers are considered a higher risk than standard, the rates charged on non-standard sub prime mortgages will be somewhat higher than mainstream rates.

But once you have been with a non-standard sub prime lender for three years, as long as you keep up your mortgage payments you will have established a new history and can return to the mainstream market with a new deal at a lower rate. Non-standard sub prime borrowers may also be referred to as 'sub-prime', 'complex prime' and 'credit impaired'.