His ruling that the general must face extradition has been one of the toughest decisions of his political life.

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Leading figures in the party did not envy him the task and privately some imagined the home secretary would not have the courage to risk a major diplomatic and political row and its consequences.

But they also believed that if Mr Straw had any ambitions in the party, he had no choice.

Mr Straw, who became home secretary after Labour's election triumph in May 1997, was forced into the unusual position of giving a final ruling on the general's extradition after Spanish prosecutors called for his arrest while he was attending hospital in Britain.

Spanish judges hope to try the general for the murder of Spanish citizens carried out in his name while he headed a brutal military dictatorship in Chile after taking power in a coup in 1973.

Speaking before the ruling, Mr Straw said his decision would be based on "quasi-judicial" rather than political reasons, with Mr Straw unlikely even to consult the prime minister on his final decision.

General Pinochet with the man he deposed, Salvador Allende

Mr Straw was lobbied extensively by the Chilean Government, who wanted to see the general's return as they feel a trial would undermine the country's fragile democracy, and those who want the general to stand trial for the estimated 3,000 murders he committed in Chile while leader.

Support for the general's return from Chile also came from the US Government and former prime minister Baroness Thatcher.

The home secretary's decision comes after Trade Secretary Peter Mandelson said in October: "I think the idea that such a brutal dictator as Pinochet should be claiming diplomatic immunity, I think for most people in this country will be pretty gut-wrenching stuff."

The decision was particularly difficult for Mr Straw as many of his Cabinet colleagues, including Chancellor Gordon Brown, campaigned against the general's regime while students.

Mr Straw has made at least one similar ruling in the past when he refused to issue an order to proceed with extradition against the IRA terrorist suspect Roisin McAliskey on compassionate grounds.

The 52-year-old started his political life on Labour's left becoming president of the radical National Union of Students in the early 1970s.

He was later an adviser to the Labour MPs Barbara Castle and Peter Shore.

After inheriting Mrs Castle's Blackburn seat he sided with the then Labour leader Neil Kinnock on the party's soft left.

He fought hardline Militants in his Blackburn constituency and after gradually moving rightwards he has become one of the strongest supporters of the Tony Blair's modernisation of Labour.

The home secretary was brought up by his teacher mother on her own after his insurance clerk father left the family home in Brentwood, Essex when he was 10.

Mr Straw married his first wife Anthea shortly after graduation from Leeds University in the early 1970s.

But tragedy struck when their infant daughter Rachel died within a week of her birth from a heart defect.

A few months later in 1978, the couple divorced, their marriage wrecked by the premature death of a child and conflicting career commitments.

In the same year, Mr Straw married his second wife Alice, who gave birth to their two children William and Charlotte.

William Straw hit the headlines last year

Before making his ruling on General Pinochet, Mr Straw hit the headlines most dramatically when his attempts to keep his family out of the news fell apart on Christmas Eve last year, when The Mirror published allegations of cannabis dealing by an unnamed Cabinet minister's son.

A frenzy of speculation rapidly descended into legal farce as court orders were imposed preventing the media from reporting that the minister was Mr Straw and the alleged dealer his 17-year-old son, William.

But, once freed by the courts to speak openly a week after the news broke, Mr Straw won admiration for his honest approach to the family crisis.