Tam Dalyell - the UK's longest serving MP - has been ordered out of the House of Commons following a dispute with the Speaker over his concerns about the Iraq crisis.

The Linlithgow MP was told to leave the chamber after he refused to obey Michael Martin's repeated requests to sit down as he raised points of order about the government's recent dossier on Saddam Hussein.

The British people have been deceived .... on a matter which is the basis of peace and war Tam Dalyell

Mr Dalyell accused the government of misleading Parliament after admitting part of the dossier was copied from an American student's outdated thesis.

Mr Dalyell, known as the Father of the House because he is the longest serving MP, eventually left the chamber unescorted.

Later, the Speaker's Office insisted Mr Dalyell had not been suspended and had merely been issued with what was effectively a final warning.

'Deceit'

The furore began after a number of MPs from all sides called for a statement on the government's dossier.

Mr Martin had privately rejected a request for an emergency debate from Mr Dalyell.

Raising a point of order on the issue, Mr Dalyell stressed: "This is a matter of trust and deceit - Parliament has been deceived.

"The British people have been deceived ... on a matter which is the basis of peace and war."

'Testing patience'

Mr Dalyell argued that the UK was on "a motorway without exit to war".

"And the basis that has been produced by a PhD student in California who now says that he is against conflict, apparently, is the heart of what purports to be the intelligence briefing of the British government."

The MP sat down, but rose again a few minutes later to reiterate his point, prompting Mr Martin to insist he resume his seat.

I think I am the first Father of the House ever to have been asked to go from the Chamber and I feel very, very strongly about it Tam Dalyell

Mr Dalyell made continued attempts to get his voice heard, but Mr Martin retorted that he had "tested the patience" of the chair and was "treading on very, very dangerous ground".

After seeking guidance from his assistants, Mr Martin eventually conceded: "I say to you that I am in the situation, very reluctantly, that I have to tell you to withdraw [from the chamber]."

Mr Dalyell replied, before leaving the Commons: "I don't want to cause you embarrassment, if this is what you wish."

'Threw in the towel'

Earlier, Mr Dalyell had complained that plagiarising an out of date PhD thesis "reveals a lack of awareness of the disastrous consequences of such a deception".

"This is not a trivial leak, it is a document on which is the basis of whether or not this country goes to war and whether or not young servicemen and servicewomen are to put their own lives at risk and indeed thousands, tens of thousands of innocent civilians," he said.

The Speaker's office said Mr Dalyell had not been formerly ordered to withdraw from the Commons.

Sir Nicolas Bevan, the Speaker's secretary said: "The Speaker asked him to return to his seat and he did not.

"The Speaker said he was on 'dangerous territory', which was a gentle warning and that did not work, and the Speaker then gave him a warning that if he persisted then the Speaker would have no option but to ask him to withdraw.

"At that point, Mr Dalyell threw in the towel and left."

'Brandishing the mace'

Outside the chamber, Mr Dalyell said he believed he had been ordered out of the Palace of Westminster for the rest of the day.

"I think I am the first Father of the House ever to have been asked to go from the Chamber and I feel very, very strongly about it," he said.

Mr Dalyell was suspended from the Commons 20 years ago when he accused Margaret Thatcher of "lying" to the Commons during the Falklands War over the sinking of the Belgrano.

Tory former deputy prime minister Michael Heseltine was suspended in the 1970s after brandishing the mace.

It has become increasingly rare for an MP to be ordered to leave the Commons.