Persimmon, which is Britain's biggest housebuilder, is currently working on a development at St Crispin in Northampton and is investigating plans to build at Dallington Heath.

Yesterday the company announced that its sales revenue for the year so far had dropped by 24 per cent and it had "postponed the commencement of scheduled new sites until the mortgage market improves".

A joint statement issued by the company's chairman, chief executive and finance director said: "Over the last three weeks the unprecedented tightening in the mortgage market has caused a further deterioration of the housing market, leading to lower sales volumes and increased cancellation rates."

The announcement was followed by a slump in shares across the housing sector.

But the company's statement said it did expect the housing market to pick up.

It said: "At some stage, in our view, housing market activity will improve, given the underlying requirement for more housing and a 'place to live' in the UK. "Given our strong financial position and scale, we remain confident in the medium and long term prospects for Persimmon."

Sue Blackman, the managing director for Persimmon Homes in the midlands, said work on the nine sites across the region which Persimmon is currently working on would continue as planned.

She said: "We can confirm that it's very much business as usual around the country for Persimmon and at Persimmon Homes Midlands.

"We have nine developments which are fully open and ready to welcome visitors as normal."