AFP - Britain was told days before invading Iraq that its weapons of mass destruction may have been unusable, a top official told a public inquiry Wednesday, adding the overall intelligence picture was patchy.

Speaking on day two of public hearings in London, senior civil servant William Ehrman said that "in the very final days before military action", Britain learned that Iraqi weapons may not have been assembled.

Witnesses also downplayed Iraq's chances of building a nuclear weapon and addressed a government claim that Iraqi leader Saddam Hussein could launch a strike with weapons of mass destruction (WMDs) in 45 minutes.

And the inquiry heard evidence of limited contact between Iraq and Al-Qaeda.

Wednesday's exchanges focused on whether Iraq had been developing WMDs. This argument was used to support the war but such weapons were never found in Iraq.

Britain received intelligence that Saddam may have been unable to use chemical weapons just days before the US-led, British-backed invasion on March 20, 2003, Ehrman said.

"We were getting in the very final days before military action some (intelligence) on chemical and biological weapons that it was dismantled and (Iraq) might not have the munitions to deliver it," the Foreign Office's then director of international security added.

"We did, I think on March 10, get a report that chemical weapons might have remained disassembled and Saddam hadn't yet ordered their assembly...

"There was also a suggestion that Iraq might lack warheads capable of effective dispersal of agents."

He stressed this made no difference to the case for war and used adjectives including "patchy", "sporadic" and "limited" to describe a series of intelligence briefings on WMDs between 2000 and 2002.

The inquiry, Britain's third related to the war, is looking at its role in Iraq between 2001 and 2009, when nearly all its troops withdrew. It will report by the end of 2010.

Former prime minister Tony Blair, who took Britain into the conflict with then US president George W. Bush, will give evidence, although not until January.

Meanwhile, current premier Gordon Brown -- another potential witness -- denied a claim the probe risks being a whitewash.

The leader of the opposition Liberal Democrats, Nick Clegg, alleged Brown's government had written to inquiry members outlining nine reasons why its final report could be censored by the government. Profile of Chilcot

"How on earth are we and is the whole country going to hear about the full truth of the decisions leading up to the invasion of Iraq if the inquiry is being suffocated on day one by his government's shameful culture of secrecy?" Clegg demanded.

Other revelations Wednesday were of links between Iraq and Al-Qaeda extremists.

"We did find some evidence of contacts between Iraqi officials and individual members of Al-Qaeda in the late 1990s," Tim Dowse, then Foreign Office head of counter-proliferation, said.

"But the judgement we came to was that these had been quite sporadic contacts... there had been nothing that looked like a relationship between the Iraqis and Al-Qaeda."

Dowse added: "After 9/11 we concluded that Iraq actually stepped further back... they weren't natural allies."

He was also quizzed about the 45-minute WMD claim.

This caused a major row in Britain at the time after the BBC alleged that the intelligence dossier containing the claim was "sexed up" to strengthen the case for war.

That was fiercely denied by the government. Government weapons expert David Kelly killed himself in 2003 amid claims he was the source of the BBC story, prompting an official inquiry. Timeline: Britain's role in Iraq

Dowse said he was not surprised by the 45-minute claim when he first heard of the BBC report, despite the "rather iconic status" it subsequently assumed.

"When I saw the 45 minutes report, I didn't give it particular significance because it didn't seem out of line with what we generally assessed to be Iraq's intentions," he said. "It wasn't surprising."

The inquiry heard that, to officials, the 45-minute claim would have referred to chemical weapons for battlefield use, not for inter-state use.

Witnesses also noted that in terms of nuclear proliferation, countries like Iran, North Korea and Libya were of greater concern than Iraq in 2001, although Saddam Hussein's "history of aggression" fuelled concerns.