Anti-Pinochet campaigners have vowed to continue efforts to bring the former Chilean dictator to trial following the UK's decision not to extradite him to Spain.

The move follows UK Home Secretary Jack Straw's ruling that the general is medically unfit to stand trial for alleged human right abuses dating back to his 1973-90 rule.

Chilean President Eduardo Frei has said he will leave it to the courts to decide whether General Pinochet should stand trial in his own country.

But commentators believe that trying the 84-year-old in Chile would not be easy - he has parliamentary immunity as a senator-for-life, as well as being protected by an amnesty.

Relatives of people who disappeared while the general was in power say they will make representations to the Uk Government over its decision.

More tests?

Meanwhile, a Chilean judge says that if General Pinochet returns home from Britain he may have to undergo further medical tests to see if he is fit to stand trial.

The judge, Juan Guzman, is dealing with the more than 50 lawsuits brought in Chile against the general by human rights groups and trade unions.

"I am going to review the possibility of requesting a legal medical report on his health - a report on both his physical and psychological condition," Judge Guzman told reporters. "Proceeding with the trial will greatly depend on that.

"I continue to study the possibility of stripping Pinochet of his legislative rights and powers."

A final decision by Britain is subject to representations by Chile, Spain - where General Pinochet faces trial on torture charges - and others within seven days. Spain has said it will not contest the decision.

But Spanish judge Baltasar Garzon, who ordered the general's extradition to Spain 15 months ago, is expected to appeal against the ruling.

Chilean trial

The Chilean Government, for its part, has maintained since the general's arrest that if he stood trial at all, it should not be in a foreign country.

On Wednesday, President Eduardo Frei said the former ruler should "face his penal responsibilities" in Chile.

"It is the courts of this country who must try Pinochet. The judges have the independence to carry out their tasks," he said.

Human rights lawyers believe that General Pinochet's immunity can be overturned in Chile's top courts. But, for the moment, it stands in the way of the cases becoming concrete charges.

If that were to happen, however, General Pinochet would probably have to face the courts, however physically ill. Chilean law only exempts people from trial if they are declared "mentally incapacitated".

"He would definitely have to face the justice system here, except if it was shown that he was mentally incapacitated - not just depressed - and that he does not understand the accusations against him," said Chilean novelist and congresswoman Isabel Allende.