Three million homeowners could end up in the trap of negative equity, with mortgage debts larger than the value of their property, as house prices continue to plunge, new City estimates show.

Bank of England calculations that the numbers caught in negative equity could soar from about half a million at present to 1.2 million by 2011, are seen as too optimistic in the bleakest assessment yet of the threat.

Michael Saunders, of Citigroup, says that the Bank's estimates are too optimistic since they are based on a survey of households where homeowners are asked for details of their own debts, financial assets and property value. Mr Saunders points to previous Bank research which showed that individuals tend to overstate the value of their homes by up to 20 per cent, and understate debts by 10-15%.

Adjusting for this bias, he calculates that a likely further drop of 15% in house prices — on top of the 15% slide over the past year — will leave between 2.5 and 3 million homeowners in negative equity. This would exceed the peak of 1.8 million, the number of people who were in this predicament in the early Nineties.

The Times