Spy chiefs warned Blair and Bush Saddam had no WMDs Pulitzer prize winner claims in explosive new book

British spy chiefs knew before the invasion of Iraq that Saddam Hussein did not have weapons of mass destruction, a new book alleges.

Ron Suskind, a Pulitzer Prize-winning reporter turned author, claims that Tony Blair and George Bush chose to ignore the intelligence on WMDs.

He alleges that the former Prime Minister authorised an MI6 agent to make contact with the head of Iraqi intelligence, Tahir Jalil Habbush al-Tikriti, in early 2003, just three months before U.S. and British troops invaded Iraq.

But when the agent reported that it was highly unlikely the Iraqi regime had stockpiles of chemical and biological weapons, his conclusions were rejected by the American military establishment, led by U.S. Vice-President Dick Cheney.

Sir Richard Dearlove, the former head of British intelligence, told Mr Suskind: 'The Cheney crowd was in too much of a hurry, really. Bush never resisted them quite strongly enough.'

The book also claims that the White House faked a letter from Saddam Hussein's intelligence chief linking Iraq with the September 11 attacks.

Mr Suskind alleges that President Bush ordered the CIA to forge the letter after the invasion to provide justification for the war.

He believes Iraqi intelligence boss al-Tikriti, who was in American custody after Hussein was toppled in 2003, was ordered to write the letter and backdate it to July 2001.

Mr Suskind claims Habbush was paid £2.5million after he copied out the letter detailing a three-day Iraqi training programme in which 9/11 ringleader Mohammed Atta had supposedly taken part.

The document stated that Atta 'displayed extraordinary effort and showed a firm commitment to lead the team which will be responsible for attacking the targets we have agreed to destroy'.

The implication is that the ' targets' were the Twin Towers of the World Trade Center struck by the hijacked planes in 2001.

The letter also hinted that Iraq was importing uranium from Niger as part of Hussein's nuclear programme.

Mr Suskind's suggestion is that in the aftermath of the Iraq invasion, President Bush was so desperate to persuade the increasingly sceptical public that Hussein was connected to the 9/11 outrage that he authorised the faking of the letter.

He writes in his book, The Way of the World, that the 'false pretences' for war and the illegal White House use of the CIA constitute an impeachable offence.

He quotes two former CIA officials who claim to have seen a draft of the intelligence chief's letter on White House stationery.

'The idea was to take the letter to Habbush and have him transcribe it in his own handwriting on a piece of Iraqi government stationery to make it look legitimate,' he writes.

A White House spokesman last night called the story 'absurd' and attacked the former Wall Street Journal reporter's credibility.

'Ron Suskind makes a living from gutter journalism,' he said.

'He is about selling books and making wild allegations that no one can verify.'