Tony Blair faced renewed pressure last night over the legality of the war in Iraq as Charles Kennedy demanded to know how he had decided there were "strong factual grounds" that Saddam Hussein had failed to dismantle his programme of WMDs.
The Liberal Democrat leader wrote to the Prime Minister calling on him to "set the record straight" as it emerged that, a year before the invasion of Iraq, senior officials had warned the Government there was no escalating threat from Saddam's WMD nor legal justification for toppling him.
The fresh question comes at the end of a week in which lawyers and MPs cast doubt on the legality of the war, and Lord Goldsmith, the Attorney General, faced a call to resign. Mr Kennedy's demand that the Prime Minister publish the entire legal advice in the run up to war follows the Iraq Survey Group's findings, published this month, that Saddam did not possess weapons of mass destruction, and the withdrawal by Jack Straw, the Foreign Secretary, of intelligence from MI6 that the Iraqi dictator could launch weapons of mass destruction within 45 minutes.
However, secret papers, including a highly confidential memo from Mr Straw to Mr Blair, which have been seen by The Independent, show that as long ago as March 2002 members of the Cabinet had been warned that invading Iraq could be fraught with legal problems. The full extent of the doubts in Whitehall is revealed in the astonishing series of confidential documents written at the highest levels of government a year before Mr Blair agreed that Britain should join the invasion.
The papers show that in March 2002 government advisers said Iraq's WMD programmes had apparently not been "stepped up", and that invading Iraq would be "legally very difficult".
An "Iraq: Options paper" marked "Secret, UK Eyes Only", prepared by cabinet office, foreign and defence policy experts on 8 March, warns: "A legal justification for invasion would be needed. Subject to law officers' advice, none currently exists." The memo adds that for the Security Council to rule that Saddam Hussein had breached his UN obligations, members would need to be "convinced that Iraq was in breach of its obligations regarding WMD and ballistic missiles". It states: "Such proof would need to be incontrovertible and of large-scale activity." But it concludes: "Current intelligence is insufficiently robust to meet this criterion."
One memo from Mr Straw to Mr Blair in March 2002, marked "secret and personal", casts doubt on the whole US rationale for pursuing Saddam Hussein. "If 11 September had not happened, it is doubtful that the US would now be considering military action against Iraq. Objectively, the threat from Iraq has not worsened as a result of 11 September. What has however changed is the tolerance of the international community (especially that of the US)."
Mr Kennedy has written to the Prime Minister asking him to clarify whether he supported regime change, and to "clarify the question of the legality of the basis on which we went to war in Iraq". "As you know, my party has never accepted that we had reached the 'point of last resort' when we went to war, because Hans Blix and the weapons inspectors had been given insufficient time to complete their task," he said.
Clare Short, the former cabinet minister, says in an interview to be broadcast tomorrow on GMTV's Sunday Programme: "I think [Lord Goldsmith] was leant on by the Prime Minister, and I don't think that safeguard in our constitution is safe any more. But the Prime Minister is the one who's really responsible. So it's no good calling for the underlings to face responsibility, when he was absolutely in control of the policy."
A confidential document from 2002 on the "background" for Iraq sets out the legal difficulties for invasion. It warns that the decision about whether Saddam had breached his UN obligations was for the UN Security Council to make - not a single member state. "The US have a rather different view," it adds.
The papers show that, a full year earlier, government advisers believed "the pace of Saddam Hussein's WMD programme" had not speeded up and intelligence was "poor".
The documents will also fuel claims that Mr Blair was pursuing a policy of regime change in Iraq but could not admit it publicly because it would have been against international law.
Sir Menzies Campbell, deputy leader of the Liberal Democrats, accused the Government of "massaging the arguments" to make the case for war. "If any of this debate had been conducted in public, then the prospect of getting House of Commons backing for military action would have been nil," he said.
A memo sent by Sir Christopher Meyer, then ambassador to Washington, after a meeting with Paul Wolfowitz, the US Deputy Secretary of Defence, in March 2002 said: "We backed regime change, but the plan had to be clever and failure was not an option."
THE LEGAL VIEW
By Robert Verkaik
Anthony Scrivener QC: "The only people who can decide whether a UN resolution is breached is the United Nations itself. The only people who can decide what remedy there should be for such a breach is the UN. I firmly believe the criteria for commencing a war were simply not met and everything that has happened since has confirmed this. It's very interesting that the Attorney General has not disclosed his full advice, so we do not know what questions he was asked to advise on."
Michael Mansfield QC: "My position has been the same throughout. The emergence of any new information makes no difference. Even if there had been weapons of mass destruction, without a second resolution and adherence to the United Nations charter there was no legal basis for going to war. Legality is dependent on legal structures being put in place. There was not a legal basis until the United Nations determined there was a legal basis. Remember what Tony Blair said to the British public, 'We will not go to war without a second resolution'.''
Peter Carter QC: "The evidence that was present before the war was always pretty flimsy; it was assertion rather than evidence. The Government did not make up its mind whether it was because Saddam Hussein represented an imminent threat to the UK or our allies. The false 45-minute claim can only have been intended to address that issue. The legal justification was not that we were at imminent risk, but the UK was entitled to say where a United Nations Security Council resolution had been breached and, in the event of such a breach, whether we were entitled to go to war. But this is not justified in law ... The international community expressed serious reservations - they were right and our Government was wrong."
Mark Stephens: "The war could have been legal because there is an emerging right of nation states to invade other states when there are human rights abuses on such a devastating and overwhelming scale ... But this war was illegal because it was based on a fundamental misrepresentation to Parliament and the British public. It was illegal because the government misled Parliament and the public ...''
Geoffrey Bindman: "The war was not legal. The UN charter says all member states shall refrain from intervening in territorial integrity or political independence of another state. There are two exceptions: collective authority given by the Security Council; and an inherent right of self-defence. Self-defence doesn't apply in this case. There was no attack by Iraq and one was not imminent, so the only legal basis was authority given by the Security Council. That authority was given in 1991 to eject Iraq from Kuwait. But there were no subsequent resolutions authorising force.