Gen Augusto Pinochet has a top-notch legal team on hand as he fights extradition to Spain.

In his QC, Clive Nichols, the 83-year-old former dictator has one of Britain's leading extradition experts, said by other lawyers to be "highly inventive". Both he and the junior QC, Clare Montgomery, come from top extradition chambers and are seen as "very hard-nosed and effective."

His solicitors, Kingsley Napley, are among a handful of firms specialising in the most difficult criminal cases, particularly fraud, which often involve extradition.

It seems likely that the general is in for a long stay in Britain. Legal experts yesterday reckoned the magistrates' court extradition proceedings and any High Court hearings could take up to two years.

He will have to adhere to any bail conditions set by the magistrate, although these may be varied. At present he must reside at a location approved by the police, and he may not leave the UK.

Pinochet's lawyers may first try to challenge the Home Secretary's authority to proceed by seeking judicial review in the High Court. This could get to court fairly quickly, though the need for his lawyers to study Mr Jack Straw's reasoning and devise ways of attacking it would probably postpone a full hearing until after the New Year.

The lawyers would have to persuade the court that they had an arguable case to get leave to bring a judicial review application. An application for leave could be heard quickly, possibly even today, and the court might "stay" the extradition proceedings so that the general would not have to appear at Belmarsh Magistrates' Court, south London, tomorrow.

Kingsley Napley would not be drawn on their plans last night. To challenge Mr Straw's decision they would have to show that he acted unreasonably or outside his powers, for example by giving undue weight to some factors or excluding others.

Paradoxically, although Amnesty International failed yesterday to obtain an injunction stopping the general leaving the country in the event that Mr Straw had decided in his favour, the result points to a likely failure for the general in his judicial review application.

Lord Justice Simon Brown, one of the most expert public law judges, held that the Home Secretary had a very wide discretion in deciding whether or not to give the go-ahead for extradition proceedings. This means that the scope for attacking his decision is correspondingly small.

An extradition expert said the High Court would also be likely to take the view that any arguments should be made to the magistrates in the course of the extradition proceedings, rather than to High Court judges.

The Privy Council has stated in a case involving the Bahamas that all the evidence should be presented to the magistrate before either side applies for judicial review. Only in the clearest cases will the courts vary this rule.

The lawyer thought the general's lawyers might decide not to challenge the authority to proceed in view of the slight chance of success.

They may still be exploring the possibility of attacking the Law lords' ruling that Pinochet has no immunity from prosecution, on the grounds that Lord Hoffmann, one of the majority of three who ruled against the general, is an unpaid director of Amnesty International Charity Ltd.

But there is no precedent for getting a House of Lords judgment set aside, and no higher court to which an appeal could be made.

The lawyers are likely to concentrate on making the general's case in the extradition proceedings before the chief metropolitan stipendiary magistrate, Mr Graham Parkinson, at Belmarsh. These could take up to six months.

The issues will be whether the crimes are extradition crimes, whether the papers from Spain are in order, and whether the alleged offences are political crimes. Lawyers said the case raised complicated questions about retrospectivity - whether the crimes charged were crimes at the time they were allegedly committed - and whether Spain has jurisdiction to try crimes committed outside its territory.

Political crimes have been defined by the House of Lords as "confined to the object of overthrowing or changing the government of a state or inducing it to change its policy or escaping from its territory the better to do so." It also connotes opposition to the state requesting extradition, so will not be a useful line of argument for Gen Pinochet.

The magistrate has no power to refuse to send him to Spain on the grounds of abuse of process, unfairness, oppression or breach of natural justice.

If the magistrate decides he should be sent to Spain to stand trial, he can challenge that decision in the High Court by judicial review or habeas corpus, an application for the release of a person from unlawful detention.

Lawyers believe it is at this stage that the general would have his best chance of success, because the argument would then shift to whether it was unjust or oppressive to surrender him to Spain.

"He would have a very strong argument for saying it would be unjust or oppressive by reason of passage of time," said one lawyer. "He can say, `I've been in and out of the country several times and nothing was done, witnesses are dying, their memories failing, I've been lulled into a false sense of security.'

"He never hid his identity when sitting in the River Cafe, and Spain could have made requests for his extradition at any time."