The die was cast: the dossiers were irrelevant

Blair did not flatly lie about the intelligence. But neither was he candid about his reason for supporting Bush

The more we dig into the deep seams of the Butler report the more appalling is the evidence we uncover on the use and abuse of intelligence in selling the case for war. Thanks to Butler we now know that the claim that Iraq possessed chemical and biological weapons ready for deployment depended on hearsay at second-hand from an original source who turned out to be unreliable. No court would have given a conviction for a speeding offence on the forensic basis of the evidence on which the Government launched an armed invasion.

The Butler committee concluded that they "were struck by the relative thinness of the intelligence base ... especially the inferential nature of much of it". Downing Street saw exactly the same intelligence but came to the opposite conclusion that it "established beyond doubt" that Iraq possessed real weapons of mass destruction.

A few sceptical questions from No 10 could readily have concluded that the intelligence was anything but beyond reasonable doubt. As Hans Blix observed last week, the Government refused "to think critically about the evidence", even when he had reported that 500 searches, including sites nominated by British intelligence, had produced no evidence of weapons of mass destruction.

Lord Butler reveals the explanation for this absence of curiosity. The truth is that intelligence was seized upon to present the case for war, but it had no relevance to the decision to go to war. For me the most crucial passage in the Butler report is its conclusion that the policy shift to a more aggressive strategy to Iraq "was not based on any new development in the current intelligence picture on Iraq". In short, Downing Street did not worry that the intelligence was thin and inferential or that the sources were second-hand and unreliable, because intelligence did not play a big part in the real reason why we went to war.

When I left the Foreign Office in 2001, we all believed that the strategy of containment was working and was denying Saddam the ability to develop weapons of mass destruction. Indeed, the thrust of our policy at the time was to tighten the embargo on military technology but to relax the sanctions on the import of civilian goods and the export of oil. The development that prompted the switch from containment to invasion was not any new intelligence on Iraq but regime change in Washington.

The Bush administration came to office with a clear agenda to displace Saddam and, to be fair, it had never made any secret of its intentions. Paul O'Neill, who was sacked as Treasury Secretary by George Bush, has since revealed that at the very first meeting of his National Security Council, Bush instructed the defence chiefs to prepare options for military action.

The Butler report records that Tony Blair informed them that it was 9/11 that increased concerns over Iraq's weapon capabilities. But it is clear that the interest of the Bush administration in occupying Iraq went back well before the destruction of the Twin Towers. For them, the significance of 9/11 was that it provided a pretext to convince Americans that invading Iraq was somehow a logical response to international terrorism.

They did this with some skill. Even now, 60 per cent of the US public believe that Saddam was behind 9/11. This is a triumph of presentation over substance even greater than selling Iraq as a military threat. Saddam knew perfectly well that al-Qa'ida was as likely to assassinate him as George Bush and he kept it out of that part of Iraq he controlled. Ironically, it is our occupation that has created the conditions in which al-Qa'ida is now thriving in Iraq - poor security, open borders and a local population with a grievance against us. The Butler report reveals that the Joint Intelligence Committee did warn that the occupation of Iraq would produce terrorist attacks on coalition forces. On this point at least, the intelligence agencies got it absolutely right.

This was a war made in Washington by an administration that chose Iraq not because it really imagined Iraq was a threat, but because it knew the country was weak and could not resist. Britain took part because Tony Blair was convinced that support for Bush's policy on Iraq was a condition of retaining our standing in the Republican White House as its most reliable ally. If the hanging chads in Florida had pointed in the other direction and sent Al Gore into the White House, Britain would just as loyally have continued with the strategy of containment and denied that Saddam was an imminent threat. There would have been no war and no "strain" on the intelligence agencies to come up with a justification.

I do not question the sincerity with which Tony Blair believes that the special relationship with America is central to Britain's role in the world. I know from many exchanges with him that it is a fixed pole of his political compass that Britain must be the closest ally of the US and he must be the best friend of whoever occupies the White House. But he never had a hope of success in selling a war on Iraq to his sceptical British public on the basis that it was necessary to stay on side with George Bush, especially when there is such a dearth of evidence that this US President pays any attention to our advice on issues from global warming to the Middle East peace process.

Democrat friends keep asking me in tones of bewilderment how Tony Blair could so effortlessly have transferred the close friendship he had with Bill Clinton to George Bush, whom they regard as at the distant extreme of the political spectrum. It is a fair question, as the close partnership with Clinton was based on shared domestic priorities and a common world vision, but neither of these applies in the case of Bush.

Tony Blair did not flatly lie about the intelligence. Lords Hutton and Butler are right about that. But neither was he candid about his real reason for agreeing to support President Bush on Iraq or about when he gave that agreement. That remains the central problem for the Government in explaining away how it ever presented a public case for war that has turned out to be built on false intelligence, overheated analysis and unreliable sources.