The annual rate of house price inflation has now turned negative for the first time since the property market began its decline, figures to be released today will show.

Hometrack, the property analyst, will say house prices have fallen by 0.6 per cent during April, leaving the market 0.9 per cent lower than a year ago.

April was the seventh consecutive month in which house prices fell, according to Hometrack, and its figures also suggest a marked deterioration of other leading housing market indicators. The average time taken to sell a home has risen from 8.5 weeks in March to 9.1 weeks this month, and the typical property now sells for just 93 per cent of its asking price, down from 93.5 per cent last month.

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While the survey suggests the property market continues to be patchy, with some variation in price falls around the country, Hometrack said this month had been the first occasion on which it had recorded declines in the majority of postcode districts. It warned that the slowdown was gathering pace, with falls recorded in 51.4 per cent of postcodes during April, markedly up on March's figure of 28.8 per cent.

While Hometrack is the first analyst to portray annual falls in house prices, its figures are broadly in line with the most recent surveys from Nationwide Building Society and Halifax Bank, the two most widely-followed property benchmarks. Figures from both suggested the annual rate of inflation was now close to zero and their next monthly updates, due within a week, could show negative growth.

Richard Donnell, Hometrack's director of research, said there was little prospect of an immediate recovery, despite a series of interest rate cuts from the Bank of England. Mr Donnell said that while a crisis in the mortgage market, with most lenders pulling their most competitive products from sale in recent months, was causing some problems, declining consumer confidence in the face of expectations of an economic slowdown was a more serious factor.

"While the availability of finance is impacting on demand in certain segments, the reality is that weak confidence is effectively resulting in a buyers' strike, with households sitting on the sidelines to see how events unfold," he said. "Transaction volumes will be the big casualty and there now seems the prospect of a record low in residential sales volumes in 2008."

Hometrack's warning of negative annual house price growth is particularly problematic for homeowners struggling with the rising cost of mortgages, particularly the 1.4 million borrowers due to come off cut-price two- and three-year fixed rates during the course of 2008.

The Centre for Economic and Business Research (CEBR) will say today that it expects more than 33,000 people to lose their homes this year after falling behind on mortgage repayments.

The CEBR, which is predicting a 10 per cent fall in average house prices during 2008 and 2009 combined, is now forecasting there will be 33,400 repossessions this year, a 23 per cent increase on last year's figure of 27,100.

"'As the credit crunch bites people will have to spend a greater proportion of their incomes on mortgages than they have done in the recent past," said Nur Ata, a senior economist at CEBR."