Idi Amin and Baby Doc will think twice before a jaunt to London

ARE THEY really trembling, all those former dictators with bloodstained hands? Is Idi Amin, in his Saudi Arabian bolthole, reading Lord Steyn's judgment with ashen face? Has Baby Doc Duvalier been down to his local travel agent on the French Riviera to cancel his plans to see Oxford Street's Christmas lights?

The membership of the club of excoriated ex-rulers is not very large these days. The deaths of Pol Pot and Mobutu took two stalwarts out of circulation, and Noriega is temporarily unavailable through being in a US jail. Others have shown little penchant for foreign travel: Galtieri and Suharto still live in their own countries, Paraguay's Stroessner stays firmly in Brazil, Ethiopia's Mengitsu in Zimbabwe. A few more linger here and there. But the former heads of state directly affected by the House of Lords judgment in the Pinochet case are few - provided they stay where they are.

The Law Lords' ruling applies only to ex-heads - not current ones. All the judges agreed that the chaps in power at present do have immunity from prosecution under international law. The likes of Castro, and the newcomer Laurent Kabila of the Congolese Republic, are safe for the moment, though the Pinochet episode gives an added incentive to dictators not to give up their power - and legal immunity - too soon. To proclaim, though, that the House of Lords has sent a warning to tyrants all over the world may make good headlines, but is a little short on realism. It's nonsense to suggest that the Law Lords' decision could make it easier, say, for the Argentine government to get a warrant of extradition against Lady Thatcher over alleged atrocities committed by British troops during the Falklands War. The law analysed in the Pinochet judgment dealt only with the immunity of heads of state. The Queen is Britain's sovereign (and as a current monarch, immune); Lady Thatcher, as prime minister, was merely its head of government.

In most dictatorships, the two are the same: the sovereign - or president, as he usually is - controls the state apparatus of repression.

The House of Lords ruling is not binding on any foreign court, though the trend, in Europe at least, is in the same direction as the British courts.

But if the direct practical results of the Law Lords' judgment are modest, the psychological impact is electric. British judges have proclaimed that our law does not provide a haven for those guilty of the grossest atrocities.

The legal question, shorn of its legal complexities, was a simple one. Does a former head of state lose his immunity if the crimes he's ordered to be committed are so vile as to amount to crimes against humanity or other acts designated as international crimes - like torture and hostage- taking? An ex-ruler, says international law, has immunity "in respect of official acts performed in the exercise of his functions". But could torture and hostage-taking be considered part of a head of state's functions? A resounding no, said the majority. If it were otherwise, Lord Steyn argued vividly, "it follows that when Hitler ordered the final solution, his act must be regarded as an official act deriving from the exercise of his functions as head of state".

Almost as important as the decision itself were the tone and confidence of the judgments of Lords Nicholls and Lord Steyn. There was none of the timidity and reluctance that is often adopted when judges feel they ought to come to a decision they don't really like. Pinochet's crimes were crimes under international law, but also, as Lord Nicholls pointed out, "it cannot be stated too plainly that the acts of torture and hostage- taking with which Senator Pinochet is charged are offences under United Kingdom statute law. This country has taken extra-territorial jurisdiction for those crimes". So much for those arguing that Pinochet's crimes were committed in Chile and therefore have nothing to do with us in Britain.

The House of Lords may not have seen the last of the Pinochet affair. The process now starting with Jack Straw deciding whether to authorise extradition proceedings is open to constant legal challenge. It is quite possible that the case will once again wend its way to the Law Lords, no longer on the issue of immunity but on the legality of the extradition or on the way the Home Secretary has exercised his powers.

It's not as simple as Jack Straw balancing the Spanish extradition request on the one hand with Pinochet's frailty on the other. Under the European Convention on Extradition and our own Extradition Act, he's obliged to give the go-ahead to the extradition proceedings - there is no exception made for the state of health of the person named in the warrant, let alone for any political or commercial considerations to come into play.

If the Home Secretary tries to use Pinochet's age or condition to send him back to Chile - either before 11 December, his new deadline for making up his mind, or after the case has gone through the legal process - his decision will undoubtedly be challenged in the courts. What the Pinochet's opponents fear is that he'll be allowed to slip out of the country secretly.

Their lawyers will be approaching Straw, asking him to promise that he won't suddenly send the octogenarian home without giving them a chance to fight the decision in the courts. The Home Secretary must be ruing the random choice that threw up those five Law Lords to sit on the Pinochet appeal. Just one judge different and the decision might have gone 3-2 the other way, and Pinochet would be back in Chile now. On such throws of the dice are the fates of dictators determined.