Tony Blair was accused yesterday of using "false pretences" to win the crucial Commons vote on war with Iraq.
Opponents of the war said they were vindicated by Thursday's report from the parliamentary Intelligence and Security Committee, and some MPs who changed their anti-war stance to help limit the rebellion in March warned that their fears had been reinforced by the summer's revelations.
But others who softened their opposition to abstain or vote with the Government in the 18 March vote stood by their decision, insisting that the dossier on Iraq's weapons was not the crucial factor in persuading them to back military action.
Anti-war MPs said their position had been vindicated by the Intelligence and Security Committee report as activists prepared an emergency resolution condemning the "illegal occupation" of Iraq to force a vote at the party's annual conference later this month.
Mark Seddon, a member of Labour's ruling national executive committeee, said: "Just as Tony Blair took Britain to war under false pretences, it is now crystal clear that he also won that crucial vote in the House of Commons under false pretences."
Brian White, Labour MP for Milton Keynes North East, was persuaded to back the Government on 18 March, despite rebelling in last September's Iraq vote. He said he "agonised" about whether to support the war in the division lobbies, but voted with the Government because he was told that a defeat would force Tony Blair to resign. He insisted yesterday that he stood by his decision. But he added: "I had a lot of doubts and I still have a lot of doubts. The doubts have been confirmed."
One Labour MP who abstained in the March vote said the details which have emerged over the summer "tighten the rope around the Government's neck".
He said: "For every day that goes by without weapons of mass destruction or evidence of WMD being found people will become more sceptical."
Clive Betts, MP for Sheffield Attercliffe, supported the Government in the votes in September and March but backed the Intelligence and Security Committee criticism of the Government's dossier on Iraqi weapons of mass destruction. Still, he said, he stood by his decision to vote for war.
He said: "I'm quite clear that Saddam probably had not got the weapons but as David Kelly argued he was taking the capacity.
"I think the intelligence committee's report was quite persuasive in saying that for public consumption there ought to have been more caveats [in the dossier]. There is a feeling around that perhaps people were not given all the information they might have been."
Hugh Bayley, MP for the City of York, said he voted for the Government in both Commons votes on Iraq, arguing that war was the lesser "of two evils", because action to topple Saddam Hussein was preferable to leaving him to terrorise his own people. "Do I say I wish we had not gone to war? We will never know the consequences of not going to war, but I suspect there would have been as many casualties or more," he said.
"I'm afraid that the strength of opposition to the dossier will deter the Government from ever publishing such a document again. Because of the dossier there was a much better informed debate."
Paul Stinchcombe, MP for Wellingborough, who voted for the Government in March, said it was "naïve" to think that MPs had not realised that a heightened terrorist threat might be one consequence of an invasion to topple Saddam.
"I will wait and see what the historians conclude. I voted against war on the first occasion and for on the second. The reason for that was something I hold to, which is that if there was going to be a war America should not be alone."
Alan Simpson, the anti-war MP for Nottingham South, said: "This raises enormous questions about the credibility of Downing Street and the process of leading the country into war. The Prime Minister said there was a real and immediate threat when there was none. He said he had evidence of current production of weapons of mass destruction and he had none.
"The fanning up of links between Saddam and al-Qa'ida was exactly the opposite of what the intelligence services were saying."Reuse content