The Bank of England has been urged not to "turn up the heat on business" by raising interest rates today.

Property market expert Harvey Williams, a spokesman for the chartered surveyors' organisation RICS, said there were "substantial concerns" about the effect of a rise in base rate.

Speaking ahead of the monthly announcement by the bank's Monetary Policy Committee at midday, Mr Williams said predictions of an increase were not backed by economic evidence.

"We have substantial concerns over the potential impact of an interest rate hike on Midland businesses and industry and would urge the MPC, at the very least, to leave the rate unchanged at the present," he said.

"This is not the time to be turning up the heat on businesses in the region."

Mr Williams' comments coincided with upbeat trading statements from housebuilders George Wimpey and Wilson Bowden.

They said improved consumer confidence and order books would help them reach full-year results expectations.

The outlook from Wimpey, Britain's fourth-biggest house builder by market value, and fifth-largest rival Wilson Bowden, echoed similar assessments from companies reporting a gradual recovery in housing demand from the sharp slowdown in mid-2004.

However, investors in both Wimpey and Wilson Bowden remained concerned about the sustainability of the recovery amid fears of higher rates and rising building costs.

"The UK housing market has been stable since the beginning of 2006," Wimpey said.

"Compared with the slow market conditions in the first half of 2005, buyer confidence this year has improved, although affordability constraints in some parts of the country mean prices remain competitive."

Total group completions for the first half rose by 19 per cent to 7,822, the highest level for 25 years, and the forward order book in Britain increased by eight per cent value to #1.06 billion.

Total UK completions increased by 28 per cent to 5,854, with private completions rising by 24 per cent to 5,138.

Wilson Bowden said its first-half forward order book rose by 52 per cent and the average selling price per unit gained six per cent to about #207,000 thanks to an increase in average unit size as well as higher prices.

However, first half housing completions at its David Wilson Homes arm were 2,135, down 2.5 per cent on 2005 (2,190), from the same average number of sites.

Smaller rival Galliford Try said its profit for the year to the end of June would be in line with expectations and substantially ahead of last year.

With build costs rising, both Wilson Bowden and Wimpey said profit margins would come under pressure, although Wimpey expected its UK margin to improve as it reduced incentives for buyers and house prices edge up.

Broker Cazenove said in a note to its clients that Wimpey's trading update was "encouraging with excellent growth delivered by the group's UK business".

Mr Williams added: "RICS can confirm that the regional housing market is healthy, but, despite the soaring temperatures, is certainly not over-heating."

Shares in Wimpey closed down 11p at 447p while Wilson Bowden was down 31p at 1452.