As Blair was basking in findings by one of Britain's most respected judges, Brian Hutton, that his government had not embellished a dossier on Iraqi weapons to bolster the case for war, a senior US weapons inspector was declaring that it was "highly unlikely" any such weapons existed in the first place.

The former head of the US team searching for weapons of mass destruction in Iraq, David Kay, called for an inquiry on Wednesday into how US intelligence services had arrived at the conclusion that Iraq was in possession of them.

"It turns out we were all wrong, probably, in my judgement. And that is most disturbing," said Kay, who headed the US-run Iraq Survey Groupuntil resigning last week.

"I believe that the effort that has been directed to this point has been sufficiently intense that it is highly unlikely that there were large stockpiles of deployed, militarized chemical weapons there," he said.

Kay, who was speaking before the Senate Armed Services Committee, first said over the weekend that he did not think Iraq had weapons of mass destruction at the time of the US-led invasion of the country last year.

Both US President George Bush and Blair have maintained that invading Iraq was justified at the time because the Iraqi leader was capable of deploying weapons of mass destruction, in some cases within 45 minutes.

But both leaders have come under growing pressure in recent months as efforts by the team sent to scour Iraq for traces of the weapons have foundered.

And more recently they and their senior officials have become more coy about the chances that such weapons will ever be found.

On Monday US Secretary of State Colin Powell said on a visit to Russia that it was an "open question" as to whether stockpiles of weapons of mass destruction were hidden in Iraq.

"There were programs that were clearly intended to produce weapons of mass destruction. They had the intention to produce weapons of mass destruction, and we knew they previously had stockpiles," Powell said.

"What we are now looking at is whether there are still stockpiles and that is an open question, but we have sent back a new chief inspector," he said.

On Monday British Foreign Secretary Jack Straw said in Brussels said the ISG's failure to find weapons programmes and stockpiles was "certainly disappointing".

But he said Britain's decision to join the invasion was "justified on the basis of all the intelligence available".

On January 11 Blair himself said it was possible that weapons of mass destruction might never be found.

"In a land mass twice the size of the UK it may well not be surprising you don't find where this stuff is hidden", Blair told BBC television, adding: "You can't be definitive at the moment about what has happened."

Asked if he had been wrong in highlighting the threat of weapons of mass destruction, Blair replied: "You can't say that at this point in time.

"What you can say is that we received that intelligence about Saddam's programmes and about his weapons, that we acted on that.

"But 'I don't know' is the answer."

On Wednesday judge Hutton cleared Blair's government of any wrongdoing in the suicide of British arms expert David Kelly, the source of a BBC report on the government's Iraq weapons dossier.

Summarizing his findings, Hutton said the BBC radio report that the government deliberately exaggerated the threat of Iraqi weapons of mass destruction before the US-led invasion on March 20 last year was "unfounded".

Hutton said it was not his remit to assess the strength of British military intelligence about Iraq's weapons of mass destruction.

But he said a BBC reporter's charge that the government made the 45-minute claim even though it knew it was wrong "was an allegation which was unfounded."

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