The 45-minute case collapses (Part 2)

The "reliable source" who provided MI6 with the information that Iraq could deploy chemical and biological weapons within 45 minutes was an Iraqi exile who had left the country several years previously, The Independent on Sunday can reveal. That fact alone should have prevented the intelligence being used in the Government's September 2002 dossier on Iraq's weapons of mass destruction.

The "reliable source" who provided MI6 with the information that Iraq could deploy chemical and biological weapons within 45 minutes was an Iraqi exile who had left the country several years previously, The Independent on Sunday can reveal. That fact alone should have prevented the intelligence being used in the Government's September 2002 dossier on Iraq's weapons of mass destruction.

The 45-minute claim, repeated four times in the dossier, is at the centre of the dispute over Britain's case for war in Iraq. An IoS investigation has established at the highest level that the "reliable source" obtained the information at second hand from a serving officer in the Iraqi army, with the rank either of full colonel or brigadier.

The Iraqi exile was in Iraq during the first Gulf War in 1991, but later fled, possibly to Scandinavia. He did not make contact with British intelligence until he was outside Iraq; last summer Tony Blair and the Foreign Secretary, Jack Straw, both told Parliament he was not a defector but "an established and reliable source". Mr Straw added he had been "reporting to us secretly for some years".

Said to have "military knowledge", the source maintained contacts with serving officers in Saddam Hussein's armed forces. But the fact that he was not in Iraq meant that the information he provided, especially on such an important point as whether Saddam had active plans to use chemical and biological weapons, did not meet normal standards for assessing intelligence, especially as it was unsupported by documentary evidence. There was no definite information on whether chemical or biological warheads were with front-line units, which would have made it feasible that they could be used within 45 minutes, or back in secure bases which would make it impossible.

The fact that the information was "single source", and was included in the dossier at a late stage, first emerged after the BBC reporter Andrew Gilligan reported what he had been told by the weapons scientist David Kelly, setting off a furore which led to Dr Kelly's suicide and the Hutton inquiry into his death.

Not until the inquiry did the public learn that the original information passed on by the Iraqi exile referred only to battlefield weapons. "It related to munitions, which we had interpreted to mean battlefield mortar shells or small calibre weaponry, quite different from missiles," John Scarlett, the chairman of the Joint Intelligence Committee and author of the dossier, told Lord Hutton.

Evidence at the inquiry showed, however, that Mr Scarlett never used the word "munitions" in drafts of the dossier, allowing the claim to become inflated to one of WMD. Sir Richard Dearlove, the head of MI6, told the inquiry that the original information was "a piece of well-sourced intelligence", though he admitted that the way it was "misinterpreted" could mean that it had been given undue prominence.

The fate of the officer who provided the information remains a mystery. There are rumours that he is dead or missing.