The letter to Ms Short was 'confidential', says Downing Street

The party's parliamentary committee - made up of representative backbench MPs and ministers - had considered whether Ms Short should be disciplined.

It follows her claim the UK bugged the UN's Kofi Annan ahead of the Iraq war.

A Labour official said anger expressed at an earlier meeting of Labour MPs had been reflected in the committee and the issue of discipline would be revisited.

Chief Whip Hilary Armstrong is to meet with Ms Short for a talk as a result of the feelings expressed by some of her fellow MPs, it has been confirmed.

Ms Armstrong is expected to make a recommendation on Ms Short's future in a week's time.

Perilous position?

A spokesman for Labour later insisted that there would be no "show trials".

Tony Blair was not be present for the parliamentary committee's discussions about Ms Short although he attended the first part of the meeting.

Kali Mountford was one of the MPs who spoke out against Ms Short at Wednesday's meeting of the Parliamentary Labour Party.

She said later the former minister was "putting herself in a perilous position" within the Labour Party.

The action which could be taken against Clare Short ranges from a reprimand to suspension or even expulsion from the Parliamentary Labour Party.

Another critic of the former international development secretary, Rochdale MP Lorna Fitzsimons, told BBC Radio 4's World at One: "Clare was in the cabinet that voted to go to war.

"She personally voted to send people to war and now she's a woman on a mission and it is just not acceptable."

Weekly meeting

One MP at the private meeting apparently said Labour's troubles in recent months had been caused not by Michael Howard but by friendly fire.

The parliamentary committee meets every Wednesday afternoon - it is a forum for the prime minister to hear the views of backbench MPs.

Ms Short said last week that the UK had spied on UN chief Kofi Annan's office in the build-up to war.

She said she had seen transcripts of his phone conversations.

Her comments were branded "irresponsible" by Tony Blair.

Principles

There have been reports Labour is planning to hold "show trials" of persistent rebels and suggestions efforts may be made to have them deselected so they do not stand as Labour candidates at the next election.

Those reports have been branded "utter rubbish" by Ms Armstrong.

Labour's Bob Marshall-Andrews, a frequent rebel against government policy, said his duty as an MP to scrutinise the executive was of greater importance than his obligation to his party.

He played down the power of the Labour leadership to put pressure on his local party adding that he had already been reselected to run as a candidate in the next general election.

But he added that the executive of the party could refuse to endorse his candidature.

"The seriousness of this, the threat, is that it does come very close to being a contempt of Parliament and I have a duty to Parliament and that's a duty to my electorate and if it conflicts then my duty to Parliament is pre-eminent."

He said he supported the government when policies were in line with the founding principles of the Labour Party.

He added: "But I will not support what appear to me to be policies which are dangerous, coercive and do not at root have anything to do with the fundamental principles of the Labour Party."