The moment the wheels of General Augusto Pinochet's jet lifted from the tarmac of the runway at RAF Waddington in Lincolnshire three weeks ago, the debate began as to the legacy of the extraordinary battle to bring the former dictator to justice.Of course, lawyers had been speculating from the moment Pinochet was arrested at a Harley Street clinic on 16 October 1998.

However, Pinochet's own solicitor, Michael Caplan, maintained a media silence throughout the 16 months of his client's forced detention.Now his client is back in the Santiago sun, Mr Caplan is happy to talk about the case that he believes raises more questions than it answers.Without a doubt it was a landmark in the history of international human rights law.

According to Amnesty International, the 'wall of impunity' sheltering former and current heads of state started to crumble from the moment of the arrest.

Amnesty claims that the UK courts had delivered a powerful message - that 'no-one is above international law' - in spite of Home Secretary Jack Straw's ultimate decision not to extradite.Mr Caplan, a partner with City law firm Kingsley Napley, believes the case clearly emphasises the need for an international criminal court to resolve such issues.

He says it is an argument that started with the signing of international conventions in the wake of the Second World War.

But that 'process', he reckons, will not be concluded overnight.He illustrates his point by reference to the terrifying images from Grozny in recent months.

'Is this country going to support a case - if there is evidence - against a former president of Russia?' he asks.

But the uncomfortable overlap between the law, politics and diplomacy is also apparent closer to home, he reckons.

What would happen if someone challenged the mandate Britain had to bomb Kosovo, he says.

'Would we be happy to argue that in an international court?'Mr Caplan cut an enigmatic figure during the case and more often than not he was by his client's side.

He was with the Pinochet entourage when it made its first appearance before the world's media at Belmarsh high security magistrates' court for the start of the extradition process in December 1998.

He almost went back to Chile with the general as the pilot, eager to leave the country, tried to take off with Mr Caplan on board.

He was there to present his client with a memento from a fan (a plate from Margaret Thatcher).Mr Caplan is a 'great believer' that solicitors should act for clients, whoever the client is and whatever the client has done.

He draws an analogy between the professional duty of lawyer to his client and that duty a surgeon owes to his patient.

It was a view shared by his firm, and there was no hesitation in taking on the client.

'Essentially these arguments were legal arguments,' he argues.

'This case was not about guilt or innocence.'Unsurprisingly, in the emotionally-charged atmosphere subtle issues of professional duty were lost on anti-Pinochet campaigners.

On one occasion, the solicitor was assaulted as he left court.

After a trip to Chile, he was criticised by one human rights group - the Relatives of the Disappeared in Chile - for 'expanding' on his role as legal representative and becoming a fundraiser.

'Nothing could be more wholly untrue,' insists Mr Caplan.

He was in Chile on his client's instructions explaining the complex legal process to, amongst others, the chief justice, the foreign minister and senior political figures.

That is what his client wanted, and he adds: 'I'd be failing in my duty not to do so.'The firm at the beginning of the case decided on the self-imposed media ban unless the client requested otherwise.

If that approach left the solicitor with his hands tied, he does not complain.

'We took the view that our function was to fight the case in the court and not in the media.'In fact, the tactic appears to have paid off and relations with the press were remarkably cordial.

'They've got a job to do and they also acted with the greatest courtesy to me on every single occasion,' he says.

Even when they were shoving a microphone in his face outside the courtroom? 'They're entitled to do that,' he says.

'That's their job.'On Pinochet's 83rd birthday in November 1998, the Law Lords overturned the High Court's decision to grant Pinochet immunity.

However, an anonymous phone call to Kingsley Napley's offices tipped off the legal team that Lord Hoffman - one of the original, presiding law lords - was an unpaid director of Amnesty.

This led to another hearing where the court overturned one of its own decisions and made legal history.

The lawyers did not get much sleep at that time, he recalls, as they were also preparing representations to Jack Straw to fight the extradition order and arranging the general's first bail appearance.The Lords also ruled that there was to be no retrospective application of the 1988 United Nations Convention against Torture.

According to the solicitor, it was a 'vitally important' decision.

As a result the number of existing charges against his client was reduced from 35 to one.After that decision, the lawyers were back in the High Court within 90 minutes to make an application to challenge Mr Straw's authority to proceed with the extradition.

The Spanish government added new charges and the Pinochet legal team was gearing up to fight them but the case never got that far.

Last November, the Home Office requested a medical examination of the general and at the beginning of the year, Mr Straw famously said he was 'minded' to release Pinochet on the basis of the reports.

Mr Caplan maintains his silence over Pinochet's medical condition.He admits that it was a 'tremendous relief' to see his notorious client return to Chile.

So has he enjoyed the last 16 months? After a long, contemplative pause he says he has.

But then adds carefully: 'From a legal point of view, it has been a fascinating case.'