A bid by lawyers representing General Pinochet to block the extradition of the former dictator began in the High Court in London on Monday.

The three judges hearing the case must decide on a writ of habeas corpus, which if allowed would free Pinochet from arrest under a warrant issued from Spain.

The Chilean government dispatched a jet complete with medical facilities and staff to RAF Brize Norton at the weekend, which now sits on the tarmac ready to fly Pinochet back to Santiago. A family spokesperson said that it was “a precautionary measure. We have to be ready for any outcome.”

Crown Prosecution lawyers are opposing both the general’s plea for a judicial review and the writ of habeas corpus. Alun Jones QC, for the Crown, told the court that Pinochet was accused of having ordered the murder, abductions, illegal detentions, torture and the disappearance of Chilean, Spanish, American, Argentinean and British subjects. The court was told that Pinochet was responsible for the killings of “at least 4,000 people”. He had also dispatched agents to Spain “to seek out and kill” opponents of his military junta.

Jones said that new evidence was being received daily by the Home Secretary Jack Straw, pointing to Pinochet’s complicity. This included allegations that while attending former Spanish fascist leader General Franco’s funeral in Madrid in 1975, Pinochet personally organised violent attacks against his opponents. The notorious Chilean secret service DINA arranged the assassinations of several prominent oppositionists in Rome and the US, as well as other countries.

Clive Nicholls QC, for Pinochet, argued that the arrest breached the general’s diplomatic immunity as a former head of state and might set a precedent whereby the Queen could face extradition for the deaths of Argentinean servicemen during the war over the Malvinas/Falklands. Nicholls said that neither British nor Spanish courts had jurisdiction to try Pinochet for any alleged crimes that occurred in Chile.

Extradition moves have also begun in Switzerland, over the 1977 disappearance of a student with dual Swiss-Chilean nationality.

It has now been confirmed that the VIP treatment lavished on Pinochet when he first arrived in the UK in September was organised and paid for by the Home Office. Home Secretary Straw was also forced to admit that this was not the first time Pinochet had received such VIP status in Britain while Labour was in power. Pinochet enjoyed the red carpet treatment last year when he arrived to discuss defence contracts.

There were demonstrations in both London and Madrid over the weekend in support of the arrest. Gale force winds and torrential rain kept the numbers small in London, but several thousand marched in Spain including human rights activists and victims of the Chilean military.

The arrest has lead to the cancelling of a visit to the UK by two Chilean navy admirals. They had been coming to discuss the purchase of several warships, worth £60 million. Vice-Admirals Hernan Couioumdjian and Onofre Torres are said to have cancelled their trip in protest at the arrest of Pinochet, who was to have brokered the deal with Royal Ordnance. A Ministry of Defence spokesman tacitly supported Pinochet’s release, saying that, “both sides believe that the satisfactory resolution of the situation concerning General Pinochet will enable dialogue to be resumed.”

Calls for Pinochet to be released continue to come from high-ranking Tory politicians. Former conservative Foreign Secretary Geoffrey Howe, now a lord, has followed Margaret Thatcher by writing a letter to the Times. Lord Howe says that the case against Pinochet, “has to be balanced against the need to promote — and then to respect — the peaceful resolution of long-running civil conflicts, which can ravage the human rights of an entire nation.” He concluded by urging “the prosecuting authorities, courts and ministers alike now to exercise discretion, to ensure that the disruptive prosecution of ex-President Pinochet that is currently in prospect does not in fact proceed.”

The High Court case continues on Tuesday.