They looked into the financial behaviour of home buyers and home owners whose loans are made up of mortgage backed securities.

These borrowers account for a massive 80 per cent of the sub-prime mortgage market, making them the vast majority of the mortgage holding population.

The number of people defaulting on their mortgage repayments has leapt up as the credit crunch really hits home.

Those worst hit are borrowers with poor credit history, among whom almost one fifth have fallen behind on their mortgage.

Delinquencies, defined as falling behind on repayments by 30 days or more rose to nearly 22% among borrowers with poor or no credit history.

Those falling significantly behind in their repayments, that is falling behind by 90 days or more, also rose, reaching double figures at almost 11 per cent.

Data also revealed that even in the high end sector of the market where borrowers have a near perfect credit rating, delinquencies have risen significantly.

According to the figures from Standard and Poor, over £7 billion worth of security backed loans are at risk of default at the moment.

Lenders must discuss matters with borrowers and agree to revised repayment plans if they are to avoid a crisis where thousands of family homes are at risk.