An inquiry into the quality of British intelligence has concluded that claims that Saddam Hussein's (search) Iraq could rapidly launch chemical or biological attacks were "poorly sourced and vague," a newspaper reported Friday.

Intelligence on the speed of such attacks was expected to be a key point in a potentially damaging report by retired civil service chief Lord Butler to be issued on Wednesday.

Butler was appointed on Feb. 3 by Foreign Secretary Jack Straw (search) to head the five-member committee looking into the intelligence claims.

The statement that Iraq could launch on notice of just 45 minutes was made four times in an intelligence dossier published by Prime Minister Tony Blair's (search) government in September 2002, as it built its case for war in Iraq.

According to London's Evening Standard newspaper, Butler will conclude the 45-minute claim "should never have been published because it was poorly sourced and vague." The newspaper did not disclose the source of its story.

Butler, the newspaper reported, also concluded that the dossier should have included vital caveats on the limits of British intelligence on Iraqi weapons of mass destruction.

The government long ago acknowledged it had just one source for the 45-minute claim, but two of Britain's most senior intelligence officials have defended the credibility of the source.

John Scarlett (search), head of the Joint Intelligence Committee which produced the September dossier, said the source was a senior Iraqi military officer.

Sir Richard Dearlove, outgoing head of Britain's foreign intelligence service MI6 told the inquiry the officer was "certainly in a position to know this information."

In Washington, the Senate Intelligence Committee said the Central Intelligence Agency fell victim to "group think" which assumed that Iraq had weapons of mass destruction — an assumption shared even by some governments which opposed the war.

"This was a global intelligence failure," committee chairman, Sen. Pat Roberts (search), said on Friday.

There was no immediate reaction in Britain to the U.S. report.

Before the invasion of Iraq, Blair was adamant that Saddam had stockpiles of fearsome weapons.

"What I believe the assessed intelligence has established beyond doubt is that Saddam has continued to produce chemical and biological weapons, that he continues in his efforts to develop nuclear weapons," he wrote in a foreword to the September 2002 dossier.

However, the Iraq Survey Group's hunt for evidence has proved largely fruitless, and Blair has retreated. "I have to accept that we have not found them, that we may not find them," Blair told a parliamentary committee on Tuesday.

Butler's inquiry aims to establish why there was such a gap between "intelligence gathered, evaluated and used by the government" and the lack of evidence on the ground in Iraq.

It has focussed on the "structures, systems and processes" of how intelligence was gathered "rather than on the actions of individuals," leading many commentators to assume that key government and security officials will not be singled out for criticism.

The 45-minute claim received extensive media coverage. It became the subject of an intense row between the government and the British Broadcasting Corp., after the BBC said Blair's office knew it was false and inserted it against the wishes of intelligence chiefs.

Three previous inquiries have cleared Blair's government of acting dishonestly or misusing the intelligence made available to it.

But more concerns have been raised about the 45-minute claim.

Parliament's Intelligence and Security Committee said in a September 2003 report that the claim was potentially misleading, as the dossier failed to make clear it referred to battlefield munitions, not missiles.

The committee also said intelligence reports failed to reflect "the uncertainties and gaps in the U.K.'s knowledge about the Iraqi biological and chemical weapons."