The prime minister has angrily rejected calls for an inquiry into the failure to locate Iraq's weapons of mass destruction.

Tony Blair used his press conference at the Evian G8 summit yesterday to label Clare Short a liar.

With Labour MPs set to intensify their demands for an investigation, Blair denied he had "duped" the country into going to war.

"I think it is important that if people actually have evidence that they produce it," he said.

"But it is wrong, frankly, for people to make allegations on the basis of so-called anonymous sources, when the facts are precisely the facts we have stated."

"The idea that apparently Clare Short is saying I made some secret agreement with George Bush back last September that we would invade Iraq in any event at a particular time is completely and totally untrue."

Writing in today's Independent, Charles Kennedy claims that the prime minister's attempts to make the case for war have seriously harmed his standing and undermined trust in the government.

Speculation is mounting however that Alastair Campbell may become the scapegoat for the controversy.

The Guardian today reports that the security services conducted a series of meetings with senior ministers in the days leading up to the war.

The meetings were said to form part of a concerted attempt to convince wavering ministers of the need to disarm Saddam Hussein.

And it notes that John Scarlett, the ex-MI6 chief and chairman of the joint intelligence committee, has denied any suggestion of a "bust-up" with Number 10 over the weapons dossier.

Meanwhile in Washington, the Senate has announced an inquiry into the way the Bush administration used intelligence information about Saddam Hussein's chemical and biological weapons.