Profile: Tam Dalyell

BBC News Online profiles the career of the UK's longest serving MP.

Tam Dalyell has proved a thorn in the side of successive governments and, despite his love of Parliament, is no newcomer to brushes with the Commons authorities.

A former national serviceman who volunteered to fight in Korea but was despatched instead to Germany, Mr Dalyell says he is not a pacifist.

But since entering Parliament in 1962, he has become most famous for his persistent critique of British military campaigns from Suez onwards.

Most notably, he harried ministers over the sinking of Argentinean ship the General Belgrano during the Falklands conflict - something he views as illegal.

That campaign saw him suspended from the Commons for accusing ministers of lying over the affair.

His questioning over the controversial sinking helped him overcome the stigma of being sacked as shadow science spokesman for his relentless opposition to the Falklands War.

Lords mire

The closest he otherwise came to a ministerial career was when he acted as parliamentary private secretary to cabinet minister Dick Crossman.

That experience has recently led him to compare Lords reform to the mire that appears in Hound of the Baskervilles.

It will surprise few people that what caused his latest exit from the Commons was his refusal to sit down without his point being heard.

During his 41 years in Parliament, he has kept on asking questions as ministers tried to fob him off.

Even in his early years as an MP, he asked 70 parliamentary questions about plans to build a military airport on a wildlife-rich area in the Indian Ocean.

And his opposition to Scottish and Welsh devolution was so fervent, that the thorny 'West Lothian Question' continues to bear the name of his then constituency.

Enoch Powell coined the phrase after Mr Dalyell had repeatedly asked why Scottish post-devolution MPs should be allowed to vote on Westminster matters when English MPs could not vote on Scottish issues.

It was a campaign that angered many in the Labour Party, coming as it did as the Callaghan government tried to secure re-election in the late 1970s.

Dressing down

Mr Dalyell is unrepentant of the way he deals with issues he believes in, once saying: "You must not be afraid to be thought a bore."

The Gulf War brought particular opposition - he predicted it could set off fires that could burn for years.

His other major spot of trouble with the Commons authorities, however, came when he leaked minutes of a select committee's meeting about the Porton Down defence research establishment to a journalist.

Despite his insistence that he thought the minutes were in the public domain, he was brought to the bar of the Commons to be upbraided by the Speaker.

As an old Etonian 10th baronet who ran the Conservative Association at King's College, Cambridge, Mr Dalyell is perhaps an unusual figure to find on Labour's left-wing.

The Suez campaign, unemployment in Scotland and being taught by left-wing economists helped ease his path away from Toryism.

The longest serving MP picks his rebellions carefully, but has not been afraid to speak his mind.

Last year, he labelled Tony Blair the worst prime minister and Labour leader he had experienced while in Parliament.

In all his years of political campaigning, he has displayed a firm flair for publicity.

This time the Speaker ultimately gave him no choice but to walk out of the Commons and into the headlines once again.