"Amsterdam is a bad treaty - it is bad for Britain and bad for Europe," he said.
But with the treaty's Commons second reading scheduled for 12 November, Kenneth Clarke, the former chancellor of the exchequer and one of the leaders of the Tories' pro-European party grouping, has already made it clear that the leadership would be foolish to go to the wall over Amsterdam.
Mr Clarke said: "The Amsterdam treaty is a fair old mouse of a treaty.
"Like most European treaties, it has some good bits and some less good, but overall it's a balanced document. It simply does not involve some fundamental transfer of power to Brussels."
So far William Hague, the leader of the Conservative Party, has given his Euro-rebels a free hand only to oppose the leadership line on the single currency.
If a three-line whip is put on the Amsterdam treaty vote in the Commons, Mr Clarke and others could be expected to vote against the Conservatives' newly hardened Euro-sceptic line - providing a measure of respective strengths.
Mr Hague said in a Daily Telegraph article on the single currency yesterday: "A small minority of Conservatives are unhappy with the party's agreed policy. "It is a perfectly honourable position and they will have a free vote if the issue ever comes before Parliament.
"But I will not allow anyone to hold our party to ransom."
Ian Taylor, the only rebel so far to have resigned from the Opposition front bench, told BBC Radio 5 Live: "I would say we are about 30 out of 165. That's not a small minority."
Any backbench Tory revolt on Amsterdam could provide the first test of numbers - excluding the hidden force of pro-Europeans within the shadow cabinet and the front-bench team in general.
The Independent understands that there are at least 36 hard-core rebels, although but Conservative Mainstream, the umbrella organisation under which the rebels will fight, said yesterday that it would not be publishing any list of MPs who signed up.
But Paddy Ashdown, the Liberal Democrat leader, said on the BBC radio Today programme that this week's events could lead to a full-scale Tory split - with MPs defecting in significant numbers.
He said it would be like the move by Labour MPs, in 1981, to leave and create a distinct and separate Social Democratic Party.
"The issue of Europe would lead to a reshaping of the British political landscape and the parallels to what happened in the Labour Party in the 1980s is compelling," Mr Ashdown said.
"Then, what started as a faction developed into an actual split of the party, eventually resulting in the formation of the SDP.
"The Tory party, in long term, needs to go through that catharsis and then come back to the centre-ground - because it is the centre-ground where elections are won.
"Mr Clarke will be waiting at the end. He is playing a long-term game."Reuse content