Tony Blair hopes to take Britain into the euro after the next general election, according to media claims.

The prime minister reportedly wants the government to agree to a pledge to work towards membership of the euro by 2007.

Plans are being considered for a referendum after a general election scheduled for June or July of next year.

On Wednesday Downing Street refused to deny the media speculation, saying people could "work out the trajectory" of timings.

It would mean that before then there would have to be another review of the chancellor's famous five economic tests and the government would have to win the referendum.

Brown is expected to rule out another review before the next general election when he delivers his Budget in March.

The government's official spokesman confirmed Gordon Brown would indeed settle the speculation.

"In the next Budget, the chancellor will make the position clear," he said.

"The position on the euro hasn't changed on what it was before Christmas."

The comments followed the Independent's report that a changeover plan put together by the Treasury predicts a four-month gap between the Cabinet's decision to call a referendum and the vote.

If the public voted for joining the euro, the Treasury estimates there would be a changeover period of more than two years before Sterling was scrapped.

The chancellor is keen to avoid another damaging row with Blair over the euro and is not opposed to Britain joining.

The sticking issue for him is economic reform in Europe but a minister told the paper he is reluctant to set a timetable.

"I don't think Gordon Brown will buy a target date. He doesn't want to make a big song and dance about the euro. But they could agree to work towards an informal target," he said.

But one Labour backbencher warned the prime minister that the issue was far from being a done deal.

"When we have a referendum it must be on the basis that it asks the public whether they want to join the euro. That's very different to asking people to back a recommendation that Britain joins," the MP said.