John Major has predicted that Britain will join the euro at some stage in the future.

But the former Tory prime minister warned Tony Blair that he would be certain to lose any referendum held during this parliament.

"The prime minister seems to be trying to manoeuvre, if you believe former close associates of his like Mr Mandelson and others, towards the possibility of holding a referendum in this parliament," he said.

"Well, I would say to him great, go ahead, hold a referendum in this parliament. I'm utterly sure you will lose it if you do."

Major accused his successor of backtracking over the euro despite being a vocal supporter of the single currency.

"The problem he now has is one of his own making. He has led people to believe consistently since he became prime minister that he is very much in favour of the euro and he would like to take us in," he told the BBC.

"If that is so, it is hard to understand why he is being quite so coy about the issue now."

Major, who retired from frontline politics at the 2001 election, claimed Blair did not have any profound belief in the European Union and had used the issue to exploit the divisions of his rivals.

"I suspect that he took many of his early European positions just to embarrass the Conservative Party and I personally doubt whether he has a great European conviction either way but I do believe that the chancellor believes it would be inappropriate to join at this time."

He repeated his call for a referendum on any new EU constitution if Blair fails to get some of the more radical proposals removed from the final draft.

"There should be a referendum on the European constitution if the prime minister cannot negotiate away the many things in the preliminary proposals that are utterly unacceptable to us. If, of course, he can, then there would be no need for a referendum.

"It is no more a tidying-up exercise than a mouse is an elephant. If it proceeds as at present proposed, it is absolutely fundamental and it makes a whole series of changes that would materially affect the way in which we are governed and the powers that parliament has."

Major comments came after the prime minister denied that senior ministers were at odds over the euro.

Tony Blair said that there was an "emerging consensus" on the issue and insisted that all members of the Cabinet were behind the principle of euro membership.

"Each member of the Cabinet, and today the Cabinet as a whole, has it made clear their support for the principle of joining the single currency with its potential benefits to Britain, British jobs and the standard of living of the British people," Blair told the media on Thursday.

"And in addition each has made it clear that that decision must be based on a rigorous assessment of our long term economic interest.

"It's the biggest decision that we face as a government and we have to get it right and I am confident that based on the discussions that we have had so far that we will."