Former Chancellor Norman Lamont said it seemed Britain was "headed for a clash with Europe" and hinted at withdrawal from the EU. If differences were not reconciled, the time would come when Britain had to consider "much more radical alternatives", he told the Commons.
A full-scale debate on the Government's approach to the conference, which opens in Turin next week, saw the sceptics howling with anger when Mr Rifkind said Britain should continue to obey the European Court of Justice.
With the 48-hour week ruling still smarting, Mr Rifkind said the Government wanted to improve the working of the court so that it did not bring its reputation into disrepute with interpretations that went beyond what was intended when laws were framed.
But when Nicholas Budgen, Tory MP for Wolverhampton SW, asked if he would hold open the prospect of Britain ignoring the court if it was not reformed, the Foreign Secretary replied: "I don't believe it would be the will of the British people to disobey the law."
"Who's law?" bellowed the sceptics. Two of them demanded Mr Rifkind make regular reports to the Commons on the IGC negotiations - a request he acceded to - though Sir Peter Tapsell, MP for Lindsey East, said they would drag on beyond the general election. "The serious negotiation won't start until then because [some states] hope they will have a Labour government to deal with," Sir Peter maintained.
Bill Cash, Tory MP for Stafford, said the Government was going into the IGC in a spirit of "appeasement" and not proposing radical plans for fear others would respond with an integrationist agenda. Patrick Nicholls, MP for Teignbridge, said Mr Rifkind seemed to be saying there would be no sticking point. He should say to Britain's partners there was a point where "we will bring the temple down" rather than give way.
Mr Rifkind said Britain favoured a "partnership of nations" and would continue to resist moves towards a "united states of Europe". He revisited the Prime Minister's "variable geometry" Europe, with different degrees of integration for different countries. The opt-out from the Social Chapter was an example and the single currency would be another.
In a more appealing section for the Euro-sceptics, he said some of the ideas for the IGC, particularly those from the Commission and the European Parliament, were driven by an "ideological mission" to maintain the momentum of integration. A clear example was more qualified majority voting (QMV) which the Government would oppose.
Those who wanted an extension of QMV really wanted it for all decisions. "But they know that is non-negotiable at the present time. So they are seeking half a loaf now, hoping to secure the other half, the flour and the whole bakery, when they can.
"That is the objective of the European Parliament, of the Commission and of a significant number of continental politicians. They want to extend QMV now as part of a long-term ambition of building a federal Europe."
But pro-European Edwina Currie, MP for Derbyshire South, said there were some Tories "who aren't nearly as frightened of QMV as the Government appears to be".
"One of our fears if the vetoes are retained in the form that they are at the moment is that the enlargement process would bring in a number of small countries, who would also have the veto. Many of us on this side do not wish to be told by small countries new to Europe what to do," Mrs Currie said.
The official opposition was kinder to Mr Rifkind, though Robin Cook, probably did not help the Foreign Secretary's standing with the sceptics by reminding them that, as backbencher, Mr Rifkind had told the Commons he believed a united states of Europe might be "a good thing".
The Conservatives were "gearing up to fight the next election on the slogan of `Bring back King Canute'," the Labour spokesman said.