Clare Short has named Gordon Brown, the Chancellor, Sir Andrew Turnbull, the Cabinet Secretary, and Eliza Manningham-Buller, head of MI5, as the three senior Whitehall figures who told her of a secret Anglo-American war pact on Iraq, according to The Times today.
Although Ms Short has not revealed her sources publicly, The Times claimed that she had identified Mr Brown, Sir Andrew and Ms Manningham-Buller in private conversations.
The former international development secretary has repeatedly alleged that Tony Blair and President Bush decided to go to war against Iraq when they met at Camp David last September.
However, all three of Ms Short's alleged sources denied having briefed her on any secret war pact. The Treasury described the claim as "complete rubbish", while the Cabinet Office and Home Office were equally dismissive.
Meanwhile, Mr Blair led a cabinet backlash yesterday against claims by Ms Short and Robin Cook that ministers had exaggerated MI6 warnings on the threat posed by Iraq.
Mr Cook said ministers deployed selective intelligence to bolster the case for war while Ms Short claimed the Prime Minister used "half-truths and exaggerations" in the run-up to military action.
But Mr Blair told MPs yesterday that the dossier on Iraq's arsenal published last September "described absolutely accurately the position of the Government".
Earlier, Jack Straw, the Foreign Secretary, denied Ms Short's claims of a war pact. He said: "We were prepared to take 'yes' for an answer from Saddam Hussein."Reuse content