There are fewer big houses for sale

The property website Rightmove says there was a 41% slump in the number of these houses being offered for sale during August, when Hips started.

It says the knock-on effect was to push down the average asking price for all properties by 2.6% or �6,298.

The report supports a similar claim this week from house surveyors.

Miles Shipside of Rightmove said: "Whilst there was a surge of 'four-bedders' coming on to the market for just one week at the end of July, there has been a much greater dearth of them in the four weeks since."

From the start of this week, it became compulsory for sellers of three-bedroom properties in England and Wales to use the Hips as well.

"Sellers like to be able to market their property immediately," said Mr Shipside.

"Introducing further hurdles and potential delays to them coming on to the market means these reforms could actually be perceived as hardening the process of moving home," he added.

'Distorted' figures

However, a spokesman for the Department for Communities and Local Government blamed August's fall in new listings on "a range of wider seasonal and market factors".

He said that August was always quiet, and that the figures had been "distorted" because some estate agents had persuaded "sellers to place their four bedroom properties on the market in advance of Hips which would result in artificially high numbers of four beds in advance of Hips, swiftly followed by an artificial low".

Rightmove claims to measure 90% of all estate agents' property adverts.

It said that until August, there were 40,000 houses with four bedrooms or more coming on the market each month.