The Lords ruled General Pinochet was not immune from prosecution and must face an extradition battle, but they reduced the number of charges and referred the case back to Home Secretary Jack Straw.

Former Prime Minister Baroness Thatcher said: "The Law Lords have now confirmed that almost all the charges brought against Senator Pinochet are inadmissible.

"In these circumstances it is quite wrong to keep him here. The judgement puts the matter firmly back into the hands of the home secretary.

"He should now bring an end to this damaging episode and allow Senator Pinochet to return to Chile," she added.

Tory leader William Hague said the ruling was a sad day for democracy.

William Hague: Send Pinochet home

He said: "Chile is now a democratic country and as such has the right to try General Pinochet for these alleged crimes in a Chilean court.

"The handling of this case has soured relations with Chile and destabilised their democracy. The right decision now is for Jack Straw to exercise his discretionary powers and send Senator Pinochet home.

"To date, almost £1m of taxpayers' money has been wasted on detaining Senator Pinochet, money that would have been far better spent on our schools, on our hospitals or on strengthening our police service."

Mr Hague added that it was time for the home secretary to "act like the senior politician he is rather than the student union president he once was".

Conservative peer Lord Lamont, who has strongly campaigned for the former Chilean dictator to be released, said the Law Lords' ruling was encouraging for General Pinochet's legal team.

He said he believed Mr Straw should now withdraw his permission to proceed with the extradition, effectively setting General Pinochet free.

"Ninety per cent of the charges against the general, in the opinion of the Law Lords, should not be offences for extradition," said Lord Lamont.

'Farce'

"They drastically scaled down the charges for extradition and therefore the home secretary should withdraw his authority to proceed.

"The whole thing is a farce. It should never have been able to get this far. The home secretary should drop it."

Anti-Pinochet campaigner Jeremy Corbyn MP welcomed the ruling. "This is a very important victory for human rights campaigners all over the world," the Labour left-winger said.

His fellow Labour backbencher Ann Clwyd, chair of the Parliamentary Human Rights Group, said: "It is very welcome news that Pinochet is not immune from prosecution and that he can be extradited to Spain."

Truth and justice

"This is an important day for the relatives of those who have suffered and who for 25 years have campaigned for truth and justice."

She added: "Those who commit crimes against humanity must be brought to justice."

Liberal Democrat deputy leader Alan Beith said: "While many of the charges will no longer be considered in relation to the extradition request, there are still serious charges against Mr Pinochet outstanding.

"This may prove to be a lengthy legal process but justice must be seen to be done at each stage.