It has been revealed that up to 80% of mortgages approved by Halifax Bank of Scotland, prior to the recession were accepted without any proof of income.

Michael Bolton, the former boss of specialist mortgage lending at the bank said: “HBOS had five brands, all offering products without proof of income.

“It was offering a lot of self-cert, a lot of buy-to-let that needed no proof of income and a lot of Halifax's mortgages were 'non-verified income' loans, which was essentially fast track.

“Before the credit crunch, as much as 80% of HBOS' loans were going through without full proof of income.”

Many underwriters have therefore stated that the bank did not make use of the traditional system of a full evaluation from an underwriter.

Halifax said it cannot be drawn on rumour or speculation. A spokesperson said: “Our underwriting approach is carried out in a responsible manner. We have one of the best underwriting approaches within the mortgage market, and the performance of our prime mortgage book is broadly in-line with many leading competitors in the market.”