British Prime Minister Tony Blair was tonight under mounting pressure to reveal if Ms Clare Short's United Nations bugging claims were true after fresh revelations of spying.
The phones of former UN chief weapons inspectors Mr Hans Blix and Mr Richard Butler were tapped while they were on missions abroad, it was claimed.
Labour backbenchers joined Liberal Democrat leader Mr Charles Kennedy in demanding the Prime Minister comes clean on the row.
But former International Development Secretary Ms Short was facing a Labour backlash after claiming British agents had bugged UN Secretary-General Kofi Annan in the run-up to the Iraq war.
British Home Secretary Mr David Blunkett refused to rule out an investigation into her apparent breach of the Official Secrets Act.
Mr Blair did not mention the matter in a speech to the Labour Party's Scottish Conference in Inverness.
Australian radio reported that Mr Blix's phone was bugged whenever he was in Iraq and the information shared between the US, Britain and their allies.
Mr Butler said he was "well aware" that his phone calls were being monitored during his tenure.
He claimed he was forced to hold confidential talks with contacts on walks in New York's Central Park because of the phone tapping in his office at the UN headquarters while he was investigating Iraq's weapons programme.
He told ABC radio: "Of course I was (bugged). I was well aware of it. How did I know? Because those who did it would come to me and show me the recordings that they had made on others to help me do my job disarming Iraq."
Mr Kennedy said Mr Blair must now tell MPs if Ms Short's claims were true.
His call was backed by Labour backbencher John McDonnell. He will table a Commons motion next week demanding to know if there was an "eavesdropping operation" and if so, how extensive it was.
Mr Blair yesterday accused Ms Short of jeopardising national security with her claims.