Britain's former deputy prime minister, Mr Michael Heseltine, emerged yesterday as the champion of a new Tory revolt against Mr William Hague's hard-line Euro-sceptic policy. Mr Hague insisted his authority as Conservative leader would withstand the challenge, that his party was not in turmoil and that he would "stick to his guns".
But the appearance for the first time of a strong pro-European force in the Tory ranks made it likely that the long-running civil war on Europe, which did so much to damage to the party, will continue to rage up to the next election.
The confidence of the pro-Europeans was underlined yesterday when the Tory MP, Mr Peter Temple-Morris, announced he had pulled back from the brink of defecting to Labour.
But Mr Hague had the bittersweet experience of hearing the Leominster MP declare his determination to fight for a Shadow Cabinet U-turn on its decision effectively to rule out single currency membership for 10 years.
He specifically pointed to the interventions yesterday by Mr Heseltine and by the former chancellor of the exchequer, Mr Kenneth Clarke, and to Wednesday's resignation by the junior Northern Ireland spokesman, Mr Ian Taylor, as key factors in his decision.
Mr Temple-Morris revealed that he had twice met the Prime Minister, Mr Tony Blair - including a meeting on Monday just after the statement on the single currency issue by the Chancellor of the Exchequer, Mr Gordon Brown - to discuss his future. He also saw Mr Blair's press secretary, Mr Alastair Campbell, and the Number 10 Chief of Staff, Mr Jonathan Powell.
A senior Labour source said later that two other Tory backbenchers were in contact with the party and were "in various stages of resignation".
"I think you might find people who just get out of the whole show," the source said. But he added: "We don't envisage any imminent defections."
Mr Heseltine issued his rallying call to pro-European Tories on BBC Radio 4's Today programme, warning that the Shadow Cabinet's 10-year "ban" on the single currency was in the interests neither of the country nor of the party.
Only a nuclear war or something of that scale would stop the single currency going ahead, he said, and "the only issue is when Britain joins, because join we will".
Mr Heseltine meanwhile was named chairman of an umbrella group, Conservative Mainstream, which aims to attract members from beyond the traditional left of the party and to find election-winning policies.
The group takes in Parliamentary Mainstream, the Progress Group of backbenchers, and the Tory Reform Group - of which the former chancellor and Euroenthusiast, Mr Clarke, is now president, giving him a place on the Conservative Mainstream board.
The left-wing McLeod group, of which Mr Temple-Morris was chairman, has agreed to suspend itself as Conservative Mainstream steps up its activities.
The shadow cabinet's decision to rule out EU single currency membership for a decade exposed a "real danger", Mr Heseltine said, adding: "You can see that at the next election we might have a Tory party fighting Britain's major companies over the issue of Europe."
Last night Mr Hague insisted he would not let himself by deflected from his European policy by "retired cabinet ministers" - a reference to both Mr Clarke and Mr Heseltine.