A Spanish judge wants the 82-year-old general extradited to Spain from the UK, where he is being held in hospital after minor surgery.

Judge Baltazar Garzon wants General Pinochet to stand trial for alleged genocide and torture during his 17-year dictatorship in Chile from 1973-90.

Monday's High Court hearing comes as speculation grows that a Chilean aircraft which has flown to RAF Brize Norton in Oxfordshire, might be used to take General Pinochet home in the event of his release.

But a source said: "The reasons for the flight are a matter for the Chileans and should not be taken to imply any decision one way or another on General Pinochet which, in any case, is not a matter for the UK Government."

Arrest 'unlawful'

General Pinochet's lawyers argue that his arrest was unlawful on several grounds including that he has immunity from arrest for actions committed while he was head of state.

Legal Affairs Correspondent Joshua Rozenberg assesses the legal battle

The Chilean Government says his detention has opened old wounds and is harming the country's transition to democracy.

A centre-right Chilean senator and Pinochet supporter who has flown over to the UK to press for his release, has warned against his detention.

Senator Evelyn Matthei said: "It is destroying our democracy. We dealt with our problems which obviously were there. No-one can deny (there were) human rights problems in Chile.

James Reynolds: New humanitarian effort to secure Pinochet's release

"But we dealt with that. We've put an end to Mr Pinochet's regime. He gave back the power gracefully and we are building a new democracy which we want to uphold.

"This is being absolutely destroyed by his detention here," she told BBC Radio 4's Today programme.

She said the Pinochet regime had resulted in economic progress, despite the human rights problems, and 74% of the Chilean population were against his detention, she claimed.

"Even people who hate him think England should not interfere," she added.

Violence broke out at a demonstration in the Chilean capital, Santiago, held on Sunday in support of General Pinochet's arrest.

More than 40 people were arrested as police used tear gas and water cannon to disperse several thousand protesters calling for General Pinochet's trial on charges of torture and genocide.