The Tories accused Mr Blair of making a U-turn ahead of next week's European Parliament elections after he said that he would not set an arbitrary timetable for British membership.
Yesterday Mr Blair insisted he had not changed his plans to call a referendum early in the next Parliament, which means that one could take place as early as the autumn of 2001.
Mr Blair was asked at the two-day EU summit in Cologne,whether his intention was to "go in at the beginning of the next parliament?" He replied: "Yes, provided, as we have always said, that the (economic) conditions are met because the conditions are real." His aides dismissed as "rubbish" and "wishful thinking" reports in Eurosceptic newspapers that the referendum might be delayed until Labour's third consecutive term in office.
Although the five economic tests set by the Government give it an escape hatch if the euro fails, Mr Blair intends to launch a drive to win public support for the new currency after the Euro-elections. He believes the British people can be won round by a campaign embracing businessmen and politicians from all parties - including the Tory heavyweights Kenneth Clarke and Michael Heseltine.
Yesterday Mr Blair accused William Hague, who has put the Tories' hostility to the euro at the heart of their election effort, of talking down the single currency after its slide on the financial markets. "It is in Britain's interests that the euro succeeds," Mr Blair said. "The Conservative Party effectively wants the euro to fail." He accused the Tories of a "betrayal of the national interest," adding: "What is in our national interest is to make sure that we do everything we can for the euro's success."
The EU summit is today expected to issue a brief statement aimed at shoring up the single currency. A German government spokesman said the EU leaders would reaffirm their commitment to economic stability. But German plans to give the euro a vote of confidence will be scrapped amid fears that this would compound the currency's difficulties.
Similarly, finance ministers, including the Chancellor, Gordon Brown, discussed plans to take a vow of silence on the level of the euro and to leave all such statements to the European Central Bank.
Gerhard Schroder, the German Chancellor, said the euro's fall "should not be exaggerated". He urged EU leaders to demonstrate their attachment to a strong euro by sending a strong signal of their commitment to growth, stability and budgetary discipline. "Nobody here has an interest in keeping the euro weak," he said.
Francis Maude, the shadow Chancellor, seized on Mr Blair's comments as proof of the Government's aim of joining the euro soon after the next general election. "Tony Blair has his head in the sand. It is astonishing that although every day brings new concerns about the euro, the Prime Minister still wants to scrap the pound for ever as soon as he can," he said.
In a rally yesterday in Plymouth, Mr Hague said that the UK could and should survive outside euroland. "These are the facts. That we do have a choice. That the euro is not inevitable. That we are the fifth largest economy in the world and we can make asuccess of our own currency and economy if we wish to do so," he said.