When you apply for a mortgage, or indeed any financial product, your credit rating is checked. A credit rating helps a lender decide whether you fit their criteria as a risk worth lending money to.

The lenders look at the reasons for your mortgage application and study your financial status and your income and outgoings. For the credit check they will use one of the two main credit reference agencies: Experian or Equifax. These agencies keep a track of your credit history - how well you have paid off your past loans and mortgages and whether you have missed any payments. Different lenders will use the results from the agencies in different ways, but there is little or nothing that won't be recorded on your file if you have had problems in the past.

It is worth keeping an eye of your credit rating via either of those agencies so you know where you stand. It is also help you to bring to light any erroneous problems on your file - which do occur from time to time. You need to raise any such problems with the agency and try and get them cleared as soon as possible.

One thing you should try and do is to avoid applying for a mortgage that you who be rejected for, as any rejected applications for credit will be show on your file and may count against you in future applications.

If you do have an impaired credit rating then you might need to look for a bad credit mortgage. Over recent years the number of brokers and lender specializing in bad credit mortgages has grown. The reason for this is that is money to be made for people providing these mortgages, thanks to the higher interest rates that the mortgages attract.

Ironically, the credit crunch, which has made life tougher for most people and helped to push more into the "at risk" categories, has reduced the number of bad credit mortgage providers.

Although it is wise to shop around, to avoid problems of multiple applications counting against your credit rating, it is best to use an independent specialist bad credit mortgage adviser. They will know how likely you are to be accepted by the lender, and help you avoid the rejection spiral.