The most stinging rebuke came from Lord Howe, the former Foreign Secretary, who, in a newspaper article today, says: "In the search for party unity at any price, UK foreign policy is being dragged into a ghetto of sentimentality and self-delusion."
MPs in the 90-strong Positive European Group of pro-EU backbenchers are poised for a fight-back with a positioning statement, to be launched possibly this week. The move will be a direct challenge to the alternative manifesto published - amid media fanfare - by eight of the nine backbench Euro-rebels without the party whip.
It also became clear that that pro-Europe members of the Cabinet are not prepared to give up without a battle and are determined that the party should not fight the next election on a Eurosceptic platform.
Nor is the pro-European lobby willing to ease its position on monetary union. Kenneth Clarke, the Chancellor, would not want to go into the next election having definitively ruled out a single European currency, even though he believes circumstances are not yet right.
Michael Portillo and the major pro-European ministers appear to see eye-to-eye on one thing, though - they are opposed to a referendum. Both camps believe such a move would be counter-productive, divisive and unlikely to address the issue effectively.
Lord Howe's remarks came after Michael Portillo, the Euro-sceptical Secretary of State for Employment, disclosed at the World Economic Forum of businessmen in Davos, Switzerland, that the Cabinet had universally endorsed at a meeting last week a decisionto use Britain's veto to stop further European integration in three areas.
These are the loss of the veto itself, changes to majority voting rights and halting increases in the powers of the European Parliament.
Lord Howe declares in the Financial Times article: "At the end of this sorry saga, we have a government that threatens to veto any future treaty involving serious institutional change, even when this is essential for the wider EU it claims to favour."
A Harris Research poll for BBC TV's On the Record yesterday suggested that fewer than one in three Britons favour a single currency.
Norman Lamont, the former Chancellor, said on Radio Four's The World This Weekend that a single currency would lead to full political union because all the economic powers governments currently have would go. The Prime Minister was "entirely right to gradually move his position as he has", Mr Lamont emphasised.
Lining up against the shift toward Euroscepticism were Sir Edward Heath, the former prime minister, Sir Peter Hordern, chairman of the Tory backbench European affairs committee, and Tim Renton, the former Chief Whip.
Sir Edward delivered a stark warning to the Prime Minister to stop publicising a negative negotiating strategy or risk attacks from his enemies when he could not deliver what they wanted.
Sir Teddy Taylor, one of the unwhipped nine, retorted: "The tragedy in the past has been that negotiations have proceeded in secrecy and our party has been presented with a fait accompli."
As Sir Edward weighed in against a whispering campaign to try to "do in" Douglas Hurd, Mr Portillo declared his loyalty to the Foreign Secretary. But he urged the nine whipless rebels to "look at what we've been saying this year".
Mr Renton said: "Michael Portillo is at times rather like a member of the Flat Earth Society. He and others often talk if we were the boss of the European Union, almost the only powerful country in it. We're not."
Ray Whitney, chairman of the Positive Europeans, but a right-winger none the less, said: "We have spent two years deliberately seeking to keep the temperature down. But a small minority is going to go on making trouble."
Hans van den Broek, the EC external affairs commissioner, and Jean Luc Dehaene, the Belgian Prime Minister whom Mr Major blocked as Commission president, said an increase of the use of Britain's veto would be unacceptable.
Leading article, page 14
Bruce Anderson, page 15