A senior Conservative Cabinet minister has warned against any move by the coalition to raise revenue by imposing higher property taxes.
Communities Secretary Eric Pickles said that introducing a so-called "mansion tax" on high value homes - favoured by the Tories' Liberal Democrat coalition partners - would be "a very big mistake".
The proposal was originally put forward by Business Secretary Vince Cable when the Lib Dems were in opposition and he has since indicated that he still favours the idea.
However Mr Pickles warned that the measure could hit "many ordinary middle class families" because of the high property prices in some areas of the country.
"We as a Government have got to understand that middle class families put a lot into this country and don't take a lot out. It would be a very big mistake to start imposing taxation on the back of changes in property values, particularly with big regional variations," he told The Daily Telegraph.
"People will suddenly find themselves in a mansion and they hadn't realised it was a mansion. If it is only going to be mansions, the kind of thing you and I would regard as a mansion, it ain't going to raise very much."
Mr Pickles warned that introducing a "mansion tax" would require a revaluation of homes across the country - something which the coalition had ruled out.
"It's a red line for the coalition. The coalition has said unambiguously that we won't be revaluing in the lifetime of this Parliament," he said.
Instead, Mr Pickles indicated he sympathised with those Conservatives calling for the 50p top rate of tax to be scrapped in order to stimulate the economy amid growing fears of a double-dip recession.
"We always said it was temporary," he said of the 50p tax rate. "I'm a Conservative, I like the idea of lowering taxation. I believe you get more tax revenue by lowering taxation because people work harder. I like people to keep more in their pockets for their family."