Mr Tony Blair will return Tory fire today with a major speech in Scotland linking "true patriotism" with his goal to see Britain in leadership at the heart of Europe.
In what is being trailed as the Prime Minister's most important speech of the election campaign so far, Mr Blair is expected to reiterate his government's five "economic tests" while saying that, if economic conditions permit, a decision to scrap sterling and join the euro could be a patriotic act in the British national interest.
Mr Blair is also certain to renew the Chancellor, Mr Gordon Brown's charge earlier this week that the true agenda of many prospective Conservative candidates is for a renegotiation of the terms of British membership of the EU, or even withdrawal.
The Conservative leader, Mr William Hague, has vowed to make the euro a daily issue for the remainder of the campaign, casting June 7th as "the last chance to save the pound".
However, Mr Blair's expected broadside coincides with mounting gloom in the Conservative camp over the latest poll evidence showing Labour still on target for a landslide win as great, if not larger, than in 1997 - and amid reports that leading pro-European Tories, including Mr Kenneth Clarke and Mr Chris Patten, are planning a "co-ordinated" push for early British entry into the European Single Currency.
With less than two weeks left to polling day, the Tory high command will also have a struggle to stop the media focus turning to the question of Mr Hague's survival - and the certainty of another leadership crisis - if he not only fails to reduce significantly Labour's present 179-seat Commons majority but actually loses some of the seats held in 1997.
Senior Labour sources at the party's Millbank headquarters yesterday were highly sceptical about the latest MORI poll for the London Times giving Labour, on 55 per cent, a staggering 25 point lead over the Tories on 30 per cent.
But the Gallup survey for the Daily Telegraph showed the Conservatives stuck on 32 per cent with Labour a steady 16 points ahead, and with only a small minority of voters positively wanting a change of government.
Worrying for Mr Hague, however - as he prepared for a protracted war of words over Europe - was the finding that only 5 per cent of those surveyed considered the European issue as "the most urgent problem facing the country at the present time", compared to 38 per cent who mentioned the National Health Service.
The only comfort for Mr Hague from both polls was confirmation that he has the advantage over Labour on the vexed question of asylum seekers, and that, according to MORI, 73 per cent of the British people remain opposed to joining the euro compared to just 27 per cent in favour.
In interviews with European journalists published yesterday Mr Blair stressed it was "patriotic" to be pro-European. "We have got to get over this idea that to be pro-British you have got to be anti-European."
However, yesterday's poll findings highlighted the dilemma which will face a second-term Blair government. The chairman of MORI, Mr Bob Worcester, said the scale of opposition to the euro was such he believed a referendum on British membership would not be held before 2005.
And the Sun's respected and informed political editor, Trevor Kavanagh, assured his readers: "Blair and Brown are devoted to the concept of the European Union, but despite this - or because of it - they will not risk bulldozing Britain into a single currency".
In an accompanying editorial, his newspaper - which was the first to declare for a second Blair term - declared: "This country has a golden future if it can resist joining the euro. If it does scrap the pound, all will be lost. Tony Blair and Gordon Brown know this only too well. Which is why the huffing and puffing about Europe is just a phoney war."