But the Prime Minister insisted during Question Time that the Government did not believe in joining irrespective of economic circumstances and denied there was a split within his Cabinet on the matter.
"Those circumstances are that there must be sustainable economic convergence and the economic benefits are clear and unambiguous, that is a perfectly plain and sensible policy," Mr Blair said
On Monday, Peter Mandelson, the Secretary of State for Trade and Industry, signalled at the Confederation of British Industry conference that it was now a matter of "when" Britain would join, but on Tuesday, Jack Cunningham, the Public Service minister, said the Government should wait and see "if" Britain should join the single currency.
In the Commons, Mr Blair said that his policy marked a "third way" between the Tories' and the Liberal Democrats' policies on joining the euro, adding that both Mr Mandelson and Dr Cunningham had outlined the position "entirely rightly".
Paddy Ashdown, the Liberal Democrat leader, repeatedly called for the Prime Minister to spell out a timetable for entry into the single currency.
He told Mr Blair: "You must answer for your policy. Let me remind you that one of your Cabinet ministers has said `when' and the other has said `if' - they can't both be right.
"When will the Government realise that this is the most important decision now facing our country?"
Replying, the Prime Minister said: "Our policy steers between the extremes of the Liberal Democrats saying they will join irrespective of the economic circumstances and the Conservatives saying they will not join irrespective of the economic circumstances. So in this case I think - the Third Way is right."
During an earlier exchange, senior Labour backbencher Robert Sheldon, MP for Ashton under Lyne, challenged Mr Blair to consider announcing the Government's intention to join Economic and Monetary Union without setting the date.
"Will that not help to underpin the Chancellor's Budget? Would that not reduce interest rates, reduce the level of the pound, improve investment and lead to that rarest of economic phenomena - a free lunch?", he said.
Mr Blair replied: "I don't agree that there is a free lunch in this set of circumstances."
He added it was important to prepare British business to handle the advent of the euro.
"It will be affected by it. When we came to office we found no preparations of any serious nature had been made by the Tory Party when in government. The worst thing we could do is stick our heads in the sand, ostrich-like, which is the Conservative Party position," Mr Blair said.Reuse content