Bit of ugly news from the BBC
By Richard Scott Personal finance correspondent, BBC News
Lenders are more reluctant to lend to borrowers
More than 23,200 people who took out 100% mortgages in the year to 31 March could face negative equity, according to figures obtained by the BBC.
Falling house prices mean the amount borrowed could be greater than the value of their properties.
The data from the Council of Mortgage Lenders comes as figures show the housing market is slowing down further.
Separate housing figures suggest the number of transactions per estate agent has hit a 30-year low.
These figures from the Royal Institution of Chartered Surveyors come as banks are imposing stricter requirements on borrowers, in the wake of the credit crisis.
If a house loses its value it is not necessarily a problem unless the owner has to move, or cannot afford to pay the mortgage.
In a rising market banks are prepared to lend 100% mortgages as there is little risk of them not getting their money back.
But as prices have been falling, the risks have increased and lenders are turning borrowers away if they don't have a deposit.
There is a warning that the situation may deteriorate further.
"House prices are down 6% in just the last five months, and the worst of the credit crisis - all that still lies ahead," said Michael Saunders, head economist at Citigroup.
He had predicted that house prices would fall by 15% in 2008 and 2009 but now he says that drop could be even greater.