The allegation was based on a White House memo -- which the programme said it had seen -- following a meeting between the two men in Washington on January 31, 2003.

The disclosures -- also reported on the Guardian newspaper's online edition Thursday -- are contained in "Lawless World", by British lawyer and university law professor Phillipe Sands, Guardian Unlimited reported.

A new edition of the book is published Friday.

In the memo, Bush is alleged to have said that military action against former Iraqi president Saddam Hussein would start on March 10, 2003. The war started 10 days later on March 20.

Bush is said to have stated that the US would put "its full weight behind effort to get another (UN Security Council) resolution" and would "twist arms" and "even threaten" to get it.

"If ultimately we fail, military action would follow anyway," Bush is alleged to have added.

Blair is then alleged to have replied that he was "solidly" behind the US president and that he was "ready to do whatever it takes to disarm Saddam".

For the British prime minister, "a second United Nations resolution (against Iraq) would provide an insurance policy against the unexpected and international cover, including with the Arabs".

On the other hand, in January 2003, less than two months before the start of the military action, the two leaders did not seem persuaded that Iraq had made any material breach of United Nations resolution 1441.

During their discussion at the White House, Bush is alleged to have said that the United States thought of "flying U2 reconnaissance aircraft with fighter cover over Iraq painted in UN colours", explaining that "if Saddam fired on them, he would be in breach".