Some senior Tories believe Mr Hague will use the commission's findings to beef up his current policy to rule out joining the euro in this Parliament and the next. "This leaves the door open for a harder line," one party source said. But such a move could provoke a bitter pre-election split with Tory pro-Europeans, led by Kenneth Clarke and Michael Heseltine.
The independent commission, chaired by Sir John Nott, the former cabinet minister, said Britain should stay out of the single currency "for the foreseeable future". The commission's report said that it would be "a supreme folly if we were to give up what remains of this country's economic independence".
Mr Hague said the findings were a "powerful vindication" of his current policy. But they also provided ammunition for Tory Eurosceptics, led by Baronesst Thatcher, who want to push Mr Hague into saying Britain should never sign up to economic and monetary union.
Sir John insisted there was no difference between his team's report and Mr Hague's policy. But he went further at a press conference, saying it was highly unlikely there would ever be sustainable convergence of the British economy and the rest of Europe. He said he could not see any circumstances where he would change his mind about British membership for 10 years.
Mr Hague said there was no reason for him to rule out joining the euro beyond the next Parliament. "We don't need to rule it out for ever. What we are talking about is what happens at the next general election. If elected, a Conservative government would keep the pound."
The Nott commission said EMU would inevitably lead to political union. "Britain will prosper with the pound. We would lose global influence if we joined the euro," it said.
The report was published as "Britain in Europe," the embryo Yes campaign for a single currency referendum, denied Tory claims that it was "a shambles" because of internal differences over its decision to tone down its support for the euro to win Tony Blair's backing.
Stephen Woodard, who is leaving his job as director of the pro-EU European Movement, dismissed speculation his departure was connected to the report's decision to soften its pro-euro rhetoric. Simon Buckby, the campaign's director, added: "[The report] Britain in Europe has built an historic coalition. The anti-Europeans are clearly rattled that Britain in Europe has cemented such an impressive alliance to argue to pro-European case."
Leading article, Review, page 3