Overt American pressure has been applied on London to allow Gen Pinochet to return home to Chile.
Chile's opposition to the extradition to Spain deserves "significant respect," the US Secretary of State, Ms Madeleine Albright, said last night in the first indication of an official US position on the dispute between Britain, Chile and Spain since Gen Pinochet was arrested in London on October 16th.
"The record of the United States in working to see those responsible for those kinds of crimes [killings and disappearances] brought to justice is second to none," Ms Albright said.
"At the same time, the United States is also - obviously - firmly committed to democracy and the rule of law in Chile," she said.
Earlier the State Department spokesman, Mr James Rubin, said: "The United States strongly condemned the abuses of the Pinochet regime when it was in power."
Chile's Foreign Minister, Mr Jose Miguel Insulza, flew out of London for Spain last night having again been told that British ministers are not open to a deal to prevent the extradition of Gen Pinochet.
Mr Insulza's four-day mission to Britain came to an apparently-abortive conclusion after the Defence Secretary, Mr George Robertson, told him he could not intervene in the conduct of the case to be determined by the Home Secretary, Mr Jack Straw, by December 11th.
As the deadline for submissions to the Home Secretary closed, Mr Robertson again told Mr Insulza that Mr Straw alone would decide whether to allow the extradition sought by the Spanish authorities to proceed before the English courts. And he echoed the earlier insistence of the Foreign Secretary Mr Robin Cook, and the Trade Secretary, Mr Peter Mandelson, that this was "not a matter for collective decision-making".
Amid reports that the United States had been applying discreet pressure to allow Gen Pinochet to return home to Chile, Mr Insulza is believed to have warned yesterday that "mutual defence interests" between Britain and Chile - specifically defence contracts - could suffer if the former dictator was extradited to Spain for alleged human rights abuses.
Mr Robertson told him he valued "our warm relations with Chile, on which we hope to build in the future". But like other ministers before him, the Defence Secretary maintained that it was for Mr Straw alone to act in his "quasi judicial role" under the terms of the Extradition Act.
Most legal experts in Britain believe the terms of last week's historic ruling by the Law Lords (that the former dictator did not have sovereign immunity) effectively limits Mr Straw to "humanitarian" grounds for any decision to halt the extradition proceedings at this stage.
Meanwhile, Grovelands Priory Hospital in North London which said it was preparing to discharge Gen Pinochet. The Speaker of the House, Ms Betty Boothroyd, yesterday overruled a Commons motion to debate the Pinochet affair, despite its sub judice nature. But the potential personal and political implications for Mr Straw were spelt out bluntly yesterday when Ms Ann Clywd, the Labour chairman of the 150-strong all-party human rights group, told the BBC that the overwhelming majority of Labour MPs wanted to see the Spanish prosecution go ahead.
"We think it's a very important decision, that it's going to signal to all those dictators guilty of torture, and genocide, and crimes against humanity, that the United Kingdom will not provide them with a hiding place, and in future they can expect the same kind of treatment," she said.
Mrs Clwyd's view was backed by Mr Donald Anderson, the Labour chairman of the influential House of Commons Select Committee on Foreign Affairs, who also urged Mr Straw to let the extradition case proceed.
The international expectation excited by the House of Lords ruling was underlined by Mrs Mary Robinson, UN High Commissioner for Human Rights - who said the decision was "extremely important in principle and heartening for human rights defenders around the world".
"We had almost become cynical about the degree of impunity for terrible acts of torture and violence around the world," Mrs Robinson told BBC Radio 4's Today programme.
In London yesterday to deliver a keynote lecture as part of the 50th anniversary celebrations for the Universal declaration of Human Rights, Mrs Robinson said that - while an international court, like that agreed in principle in Rome recently, was needed to try such crimes - in the meanwhile current law must be used effectively to bring human rights criminals to justice.