An unnamed senior British minister told the Independent newspaper that the failure to find weapons of mass destruction (WMD) in Iraq would constitute "Britain's biggest ever intelligence failure" and trigger an overhaul of the security services.

And Jane Harman, the senior Democrat on the US's House Select Committee on Intelligence, told The Times: "This could conceivably be the greatest intelligence hoax of all time. I doubt it, but we have to ask," added.

"It was the moral justification for the war. I think the world is owed an accounting," Harman said.

"My concern is that we did not have enough good intelligence to draw the necessary conclusions that our policy makers need to be completely confident," Peter Goss, the committee's Republican chairman told The Times.

"Wouldn't it be nice if we gave them better information to base their judgements on?" Goss asked.

The intelligence committee has written to George Tenet, the CIA director, asking him to respond by July 1 on several key questions, with a view to holding hearings later that month.

The letter, which the Times said it had seen, asks Tenet whether the intelligence was of sufficient quantity, quality and reliability, how it was analysed, and whether "any dissenting views were properly weighed."

"The committee is interested in understanding how the CIA's anlaysis of Iraq's linkages to terrorist groups, such as al-Qaeda was derived," the letter says, according to the same source.

In Warsaw on Friday, Prime Minister Tony Blair dismissed as "completely absurd" the idea that intelligence agencies fabricated evidence that Iraq had weapons of mass destruction in order to justify war.

"The idea that we asked our national intelligence agencies to invent some piece of evidence is completely absurd," he said.

Opponents of the Iraq war were "now trying to find fresh reasons why it was not the right thing to do," he added.

The Daily Telegraph said that the issue was far graver for Blair than for US President George W. Bush, who presented a far wider public case for war than the British leader did in the House of Commons.

"Blair, desperate for the support of his own party, nailed himself firmly to the mast of WMD (weapons of mass destruction) and allowed his spin machine to exaggerate the danger to Britain," the newspaper said.

British government officials, quoted in the Financial Times, said that British and US military planners were depending on Saddam Hussein's regime using its weapons of mass destruction as proof that Iraq possessed them and were not expecting to mount a widescale hunt for a hidden arsenal.

WAR.WIRE