Blair himself set the tone by describing Short's revelation as "deeply irresponsible" and telling followers in his ruling Labour Party that her claims were providing ammunition for his political opponents.

Home Secretary David Blunkett, Britain's interior minister, and other senior party figures also jumped into the fray, accusing Short of personal vindictiveness against Blair.

Short, the former international development secretary, quit in May in protest over the Iraq invasion.

She made her claims about spying on Annan's office after British prosecutors dropped charges against an intelligence translator, Katharine Gun, who leaked a memo revealing apparent US plans to spy on members of the UN Security Council in the run-up to the war.

Short said transcripts of Annan's bugged telephone calls were circulated to senior British ministers.

While Blair aides attacked Short, opposition members demanded that the prime minister say whether she was telling the truth or not.

Blair also came under pressure to reveal the legal reasoning for joining the invasion of Iraq alongside the United States last March.

The government refused, other than to say that it had advice of the Attorney General, Lord Peter Goldsmith, the nation's top law official, that the war was legitimate under international law.

Political commentators said the government may have ordered the official secrets charges against Gun dropped because a trial might have revealed details of the pre-invasion planning.

Nevertheless, the environment organisation Greenpeace demanded publication of Goldsmith's advice in the defence of 14 of its activists who briefly seized armored vehicles being shipped to Iraq to dramatize their allegation the war was illegal. They were scheduled to go on trial March 9.

Michael Howard, leader of Britain's opposition Conservatives, also demanded the government publish the attorney general's advice in full.

So far only Goldsmith's conclusion that the war was legal has been published.

While the political row rumbled on, other prominent UN figures lent credence to Short's charges.

Former UN secretary general Boutros Boutros Ghali, and former UN chief weapons inspectors Richard Butler and Hans Blix all said they had reason to believe they were spied upon.

Blunkett denied Short's allegations that transcripts of bugged phone conversations circulated in British cabinet meetings.

"I wasn't shown any transcripts and I am one of the very few people -- and Clare Short is not one of them -- who have clearance for the full security material that comes through," Blunkett told reporters.

Former government minister Jack Cunningham said Short had a personal agenda "to attack, damage and undermine the prime minister at every opportunity and sadly, that's been the hallmark of her conduct and behavior since she left the government."

Amid calls for Short to be expelled from Labour, party chairman Ian McCartney condemned her behaviour as "outrageous and unforgivable", but said he was not "going to make her a martyr".

Short, meanwhile, was unrepentant.

She repeated her allegations in an op-ed article in The Independent newspaper, saying Blair had to deal with two key allegations: "one that the attorney general's legal advice authorising war in Iraq was manipulated in dubious ways, the other that Britain is intruding on the privacy of Mr Annan's phone calls."

Short said Blair was not a man for details and may have been unaware of spying at the UN.

She added: "The suggestion that there is any threat to our national security or intelligence services from the exposure of the fact that such transcripts are circulated is laughable."

The issue is potentially explosive for Blair, and illustrates the formidable pressure that Britain and the US placed on members of the UN Security Council to vote a resolution explicitly authorizing a resort to force.

No such resolution was passed, and Britain had to justify the invasion of Iraq on the advice of the attorney general, without which, Short said, military commanders would not have moved.

A coalition of groups opposed to the war said Saturday it intended to take legal action over "the mass murder of 20,000 or so Iraqis" against Blair and US President George W. Bush before the International Criminal Court in The Hague.

Some 600 supporters of the Stop the War coalition, which was formed in September 2001, met in London to prepare for a mass demonstration in the capital on March 20, the anniversary of the invasion of oil-rich Iraq.

TERRA.WIRE