Tony Blair was sent three intelligence reports in the six months during the run up to the Iraq war, including one that warned him that information on whether Saddam Hussein still held any chemical or biological weapons was "inconsistent" and "sparse".
The revelation adds to the mystery of how the Prime Minister could tell Parliament last week that, when war began, he still believed that Iraq held weapons of mass destruction capable of being deployed in just 45 minutes.
That 45-minute claim, highlighted in a dossier which Mr Blair presented to the Commons in September 2002, inspired reports in the press that British servicemen and tourists in Cyprus could be hit at any moment by long-range Iraqi missiles.
In fact, John Scarlett, chairman of the Joint Intelligence Committee (JIC), and the Secretary of State for Defence, Geoff Hoon, knew that it was only "battlefield mortar shells or small-calibre weaponry" that could be deployed that quickly - but seemingly nobody told the Prime Minister, who said in the Commons last week that he did not find out until after 18 March, when MPs voted to go to war.
Yesterday Robin Cook, the former foreign secretary who resigned as Leader of the House in the run-up to the war, urged the committee of inquiry set up under Lord Butler to investigate why a vital piece of information was apparently withheld from the man who made the decision to send British troops in to fight.
Mr Cook, who is due to be interviewed on the ITV's Jonathan Dimbleby programme today, said: "One of the questions the Butler inquiry must ask is why on earth the JIC sent up three assessments of Saddam's weapons capacity without making it clear that they were talking about battlefield weapons, not strategic systems."
The committee, chaired by the former chief whip Ann Taylor, supported Tony Blair's claim that Saddam Hussein and his weapons of mass destruction posed a threat to Britain, and that - by implication - the Prime Minister was right to take part in a war without UN sanction.
They gave two reasons: that the Iraqi army, with or without weapons of mass destruction, might attack UK forces policing "no-fly zones", or that they might fire Al Hussein missiles at British forces in Cyprus.
Last week the Government slipped out a follow-up document, with the clumsy title Government Response to the Intelligence and Security Committee Report on Iraqi Weapons of Mass Destruction, which was placed with minimal publicity in the Commons Vote Office.
The document makes the startling revelation that the intelligence services had already reported, before the war began, that Iraq's ballistic missiles had probably been dismantled, and that the presence of UN weapons inspectors in Iraq was making it difficult for Iraq to threaten anyone with weapons of mass destruction.
The document added: "The JIC assessments produced in October and December 2002 and again in March 2003 reflected this point. In December 2002, the JIC specifically pointed out that Iraq's ability to use chemical and biological weapons (CBW) might be constrained by the difficulty of producing more whil. UN inspectors were present.
"In March 2003, [the JIC] stated that intelligence on the timing of when Iraq might use CBW was inconsistent and that the intelligence on the deployment was sparse.
"Intelligence indicating that chemical weapons remained disassembled and that Saddam had not yet ordered their assembly was highlighted. The JIC also pointed out the intelligence suggested that the 750km-range Al Hussein ballistic missiles remained disassembled and that it would take several days to assemble them once orders to do so had been issued."
The Liberal Democrat leader, Charles Kennedy, has defended his party's decision to boycott the Butler committee, saying that it "allows the wrong questions to distract attention from the real issues."
Writing in today's edition of The Independent on Sunday, he said: "What the Prime Minister has really done this week is to tell us to take it or leave it.
Forget inquiries - the people will be his judge."
Peter Hain, the Leader of the House, admitted last night that Mr Blair was no longer "unassailable". After seven years in power, he said, Labour had "hit our first very seriously choppy waters."
* Tony Blair has written to the widow of Dr David Kelly offering a private meeting, according to her lawyers. Janice Kelly declines to say whether she intends to accept his invitation.Reuse content