Clare Short, left, and Kofi Annan

The allegations have sent political shockwaves through Britain, which remains deeply divided over whether it was right to invade Iraq last year.

Interviewed on BBC radio, former International Development Secretary Clare Short said British intelligence was involved in a bugging operation at the United Nations.

"These things are done, and in the case of Kofi's office, he has been done for some time," she said.

"Well I know. I have seen transcripts of Kofi Annan's conversations," replied Ms. Short when asked if she believed Britain had been involved in it. "In fact," she said, "I have had conversations with Kofi in the run-up to war, thinking, 'Oh dear, there will be a transcript of this, and people will see what he and I are saying.'"

Ms. Short answered "Yes, absolutely" when BBC reporter asked if British spies have been instructed to carry out operations within the United Nations on people like Kofi Annan.

Ms. Short resigned from the government just after major fighting ended in Iraq, saying the war was not justified.

At a news conference later, Prime Minister Blair would not confirm or deny the claims.

"I am not going to comment on their operations, not directly, not indirectly," said Mr. Blair. "That should not be taken as any indication about the truth of any particular allegations, and I think the fact that those allegations were made is deeply irresponsible."

Mr. Blair maintained that Britain's intelligence and security agencies act in accordance with domestic and international law.

This latest controversy comes the day after British prosecutors dropped charges against a former employee of the Government Communications Headquarters, who was charged in connection with the leaking of a secret document related to eavesdropping at the United Nations.

The official, Katharine Gun, admitted to leaking a memo from a U.S. intelligence official asking for British help last year in getting information about members of the Security Council that had not announced how they might vote on an Iraq resolution. The memo did not say what kind of help was needed, but the Government Communications Headquarters specializes in monitoring telephone calls, e-mails, and other types of communications.