Trade and Industry Secretary Peter Mandelson went on to describe as "gut-wrenching" the Chilean Government's protest that General Pinochet was protected by diplomatic immunity.

The former military leader was arrested in London on Saturday at the request of Spanish judges investigating murders allegedly committed during his 17-year reign.

Chile claims that General Pinochet, as a life senator in his own country, should enjoy diplomatic status, but the UK Foreign Office has already rejected the idea.

Peter Mandelson: Rejects diplomatic immunity

Mr Mandelson confirmed the government's position when he told BBC TV's Breakfast with Frost: "The idea that such a brutal dictator as Pinochet should claim diplomatic immunity I think for most people in this country would be pretty gut-wrenching stuff."

He said that Home Secretary Jack Straw would judge the Spanish extradition request "on the basis of the law".

The 82-year-old former dictator was detained by police while in London for a back operation.

Scotland Yard will not disclose his whereabouts, but it is thought that he is being held in a west London clinic where he is recuperating after surgery.

General Pinochet ruled Chile for 17 years until 1990, during which time it is alleged that 3,197 political opponents were killed, with a further 1,102 people still unaccounted for.

Spanish judges are investigating allegations that General Pinochet murdered Spanish citizens in Chile between 11 September 1973 and 31 December 1983.

'Ghastly dictator'

The arrest of General Pinochet drew a welcome reaction from politicians and human rights groups.

Chairwoman of the House of Commons human rights group, Labour MP Ann Clywd, said she would be calling for "close co-operation" with judges Baltasar Garzon and Manuel Garcia Castellon, both of whom are in London to question the former dictator.

Left-wing Labour MP Jeremy Corbyn said General Pinochet was "one of the great murderers of this century".

"It will be the first time this ghastly dictator has faced questions," he said.

Liberal Democrat Foreign Affairs Spokesman Menzies Campbell said: "There should be no hiding place for those who are responsible for serious breaches of human rights.

"And Britain should not be regarded as a safe haven for dictators seeking to avoid the consequences of their actions."

'Important lesson'

Amnesty International spokeswoman Virginia Shoppee said General Pinochet's arrest served as a warning to other dictators that they cannot escape their past crimes.

"I certainly think that this is a lesson that is very important.

"On the one hand it is possible for the British Government to show that they are very serious about this business of the policy of human rights and also for all those dictators who are considering that Europe is a safe haven, well they are going to learn that they have to answer for what they have done in the past, that the past is the present."

General Pinochet retired as commander-in-chief of the Chilean armed forces last March.

The Chilean constitution, which he effectively wrote in 1980, enshrines his right to an unelected seat for life in the Chilean senate.