More than a fifth of UK homebuyers who have a chequered credit history have fallen behind on their mortgage payments and even those with top-quality ratings have seen a statistically significant rise in delinquencies in the first three months of this year.

New data from Standard & Poor’s provides the first glimpse into how mortgages are performing this year. It is based on the behaviour of homebuyers whose loans have been packed into mortgage-backed securities – which accounts for 80 per cent of the £43bn subprime mortgage market.