Tory leader David Cameron was joined by Labour MPs in calling for a plebiscite on any transfer of powers to Brussels.

The row came after French President Nicolas Sarkozy said he had reached agreement with Mr Blair on the "framework" of a new treaty to be agreed at an EU summit later this month.

His comments sparked fears of a revival of the controversial EU constitution defeated by French and Dutch voters in referenda two years ago.

Mr Cameron signalled he would push for any move with implications for Britain's powers to be put to the public - potentially landing incoming Prime Minister Gordon Brown with a massive headache.

"Any treaty that is about the transfer of powers to the EU must be put to the country in a referendum," Mr Cameron told The Sunday Telegraph.

According to the newspaper, the new treaty will establish a permanent EU president with a two-and-a-half year term of office and create a new EU foreign minister. There will also be a review of voting rights, cutting Britain's influence in Brussels and putting at risk Britain's opt-out on issues like the working time directive.

Tory donor Stuart Wheeler and former Cabinet minister John Redwood both backed Mr Cameron's call. Lynne Jones, Labour MP for Birmingham Selly Oak, also said: "I have always felt we should have a referendum if the changes are of a fundamental nature."

A Downing Street spokesman said: "The Prime Minister and President Sarkozy did discuss the EU treaty. There is broad agreement in the sense that they both think that any treaty must be an amending one rather than a constitutional treaty.

"The Prime Minister has said before that if we have an amending treaty, as in Nice and Amsterdam, then a referendum would be unnecessary."