Although Conservative Central Office appeared to be backing John Horam, a health minister, and James Paice, an education and employment minister, opposition parties were claiming that they had clearly breached the "negotiate- and-decide" policy on the single currency. Labour said the Tory party was disintegrating.
The Prime Minister was already on the defensive yesterday over Euro-sceptic remarks by Dame Angela Rumbold, a Conservative Party vice-chairman, even before news broke late last night of the latest open defiance of the Cabinet line.
Earlier yesterday, Tony Blair had said that if John Major was re-elected the Tories would fight "like ferrets in a sack".
In addition to saying he was opposed to the replacement of the pound with the euro, Mr Horam had said he would want a referendum on any other major issue of constitutional issue which went beyond current policy. Last night, the Conservative MP for Stamford and Spalding, Quentin Davies, suggested that ministers who broke the line should have to resign.
"The general position is quite clear. The public is entitled to assume that no government can speak with forked tongue. I assume that Mr Horam supports the government policy. In the theoretical event that a minister no longer found it possible to support the government policy that would be the only sensible course for him to take," he said.
However, Bill Cash, Euro-sceptic rebel and MP for Stafford, said Mr Horam had not broken the line: "He has made it clear that he is being absolutely honest with his electorate. Malcolm Rifkind [Foreign Secretary] has expressed himself as being hostile.
It is perfectly clear that the whole of this single currency question goes to the very heart of who governs Britain," he said.
Last month on BBC's Newsnight programme Mr Major insisted that no minister was going to take such a position. "Members of the Government are going to issue a manifesto that will precisely mirror the national manifesto of the Conservative government," he said.
Senior Conservative aides had added that no dissenters should remain in office, but last night the party was left in an impossible position. If it sacked the rebels, there would be bound to be a backlash from Euro- sceptics, commentators said.
Earlier, Mr Major had defended Dame Angela, saying she was not a minister and could therefore speak her mind on Europe. However, that position looked decidedly threadbare with the more serious breach of the Tories fragile stance by Mr Horam.
Tory divisions on Europe looked set to dominate the election agenda again today, causing irritation among the Conservative high command.
Horam and Paice: rebels who have rocked the boat
John Horam, Junior Health Minister
John Horam is a man used to dramatic switches in fortunes having served in Tory and Labour governments - and for a time he also sat as an MP for the Social Democrats.
A year ago, as a right-wing junior health minister, he told local authorities to close old people's homes where private enterprise could take over the work more cheaply.
But he entered Parliament at the other end of the spectrum, as a Labour MP sponsored by the Transport and General Workers' Union. That was in 1970, when he became MP for Gateshead West, a Labour safe seat. By 1976, he was Under-Secretary of State for Transport, a post he held until the 1979 election.
In January 1981, he and two other Labour MPs broke ranks by announcing support for a Liberal Party 10-point economic recovery plan. By the end of the month he was nailing his colours to the mast of the newly-formed "Council for Social Democracy", nucleus of the new SDP. He spent the next two years, until 1983, as an economics spokesman for the SDP. That ended when at the 1983 general election, when he stood unsuccessfully for the SDP in Newcastle upon Tyne Central.
He joined the Tory party in February, 1987, and was selected for Orpington, where he was elected in 1992.
James Paice, Education Minister
James Paice has long been known to be on the right of the Conservative Party. Tall and balding with an accent described by The Almanac of British Politics as "classless" and "cockneyfied", he voted for the reintroduction of capital punishment and against any lowering of the age of homosexual age of consent in 1994.
In 1993, he launched a campaign on behalf of the British Association for Shooting and Conservation to encourage young people to use firearms, a proposal dismissed by the Labour MP Alan Milburn as "dangerous nonsense".
He was appointed Under-Secretary of State for Employment in 1994, moving to the Department for Education and Employment when the two offices were merged the following year.
Mr Paice was elected for South East Cambridgeshire when the seat was created in 1983, and was known at first as a representative of the agricultural industry in a primarily rural seat. Now 48, he was a farmer during the 1970s after being educated at Framlingham independent school in Suffolk and Writtle College of Agriculture in Essex.
His seat is among the Conservatives' 40 safest, with a notional majority over the Liberal Democrats of 21,000 under new boundary arrangements.Reuse content