Unveiling the Liberal Democrats' manifesto for the European Parliament elections on 10 June, Mr Ashdown said the Government's greatest failing was its "timidity" on the euro and its "absolute failure to set a lead on this great issue".
The Liberal Democrat leader said Labour was "sitting on the fence" on the biggest decision it faced, while the Tories were saying "please stop the world, we want to get off". He said: "We can offer leadership in a way the Government is not."
In a surprisingly strong attack, Mr Ashdown likened Mr Blair's prevarication to John Major's handling of the issue, saying that Europe was driving him rather than the other way round.
Mr Ashdown predicted that Mr Blair would change his policy by calling a referendum on whether Britain should join the euro before the next general election - a claim dismissed later as "fanciful" by ministers.
Although the Liberal Democrat manifesto calls for reform to tackle the European Union's failings, the party is risking alienating some voters by adopting an unashamedly pro-single currency stance. "If people want more investment, more jobs, more influence in Europe, there is only one party to vote for," said Mr Ashdown.
But he said voters could also vote Liberal Democrat to send a message to the Government that "doing a little bit better than the Tories on health and education is simply not good enough". The manifesto called for a referendum on the single currency to be held as soon as possible; completion of the single market and expansion of the EU.
Today William Hague, the Conservative Party leader, will put the single currency at the heart of the Tories' Euro election campaign by saying they are the only party who would "keep the pound".
He said he would never agree to surrendering control of Britain's economy to Brussels. Aides said he was "inclined" to believe that joining the euro would involve such a surrender.Reuse content