Perhaps not the best week then for the society to issue a mortgage making it easier for borrowers with small deposits to enter the property market, you might think.

It expects these long-run gains because the cost of its borrowing will be less than the interest payments on the new mortgages issued.

These rules require lenders to hold more capital when issuing a mortgage, leading to higher costs which will be passed to customers.

The number of mortgages issued rose by 5 per cent last month, as banks gained the confidence to issue higher-value loans.

Approximately 90% of subprime mortgages issued in 2006 were adjustable-rate mortgages.