Lord Justice Nicolas Browne-Wilkinson announces the decision

Amnesty International chairman Andy McEntee said: "We are disappointed in terms of the time and effort expended and in terms of having to come back and do it all over again.

"But we always said we would accept the outcome of the hearing and we have no problem with it now.

"Our view has always been that everyone has their right to a fair trial, one that is also seen to be fair."

He added: "Augusto Pinochet has very inventive lawyers. They are very good, very effective. They will make this a long case, one that is hard for him to lose."

The Spanish judge seeking the extradition of Gen Pinochet reacted with surprise to the decision.

Andres Zaldivar: New hope

But court sources said Judge Baltasar Garzon, who successfully sought Pinochet's arrest in London in mid-October, remained confident the latest decision would not derail his two-year-old investigation of Latin America's "dirty wars".

Andres Zaldivar, speaker of the Chilean senate, welcomed the decision.

"What has happened today inspires new hope that this matter can be resolved in London."

Total shock

Carlos Reyes, spokesman for Chile Democratico and Chileans in Exile, said he feared the decision would lead eventually to the collapse of the case against the former dictator.

He said: "I am in total shock at this decision. It appears that the Law Lords have ruled that anyone who is concerned with human rights could be biased in this case.

"Many of the lawyers who are working for Pinochet are concerned with human rights. It is completely wrong.

"It seems to me that this could be a way out for Pinochet."

Jose Miguel Insulza: Surprised

Chilean Foreign Minister Jose Miguel Insulza said he was surprised at the decision.

"Every topic in this case has been a surprise, starting with his original arrest," he said.

Jack Lang, head of the French National Assembly's Foreign Affairs Committee."This decision is appalling.

"I hope it is only a blip and that Britain will take the judicial steps needed to bring Pinochet to trial."

The Conservative former UK Chancellor Lord Lamont, who has been a leading critic of the extradition attempt, welcomed the ruling and called for the case to be swiftly resolved.

"Any other decision would have left the reputation of British justice compromised," he said.

"It is essential this case is completed quickly. Justice delayed is justice denied."

Ann Clwyd MP: It is a great shame

The Lords' decision prompted severe disappointment in the Parliamentary Human Rights Group.

Chairwoman Ann Clwyd, the Labour MP for Cynon Valley, said: "It is a great shame that the process in the House of Lords will have to start again. We believed real progress was finally being made.

"The families of the disappeared and the victims of his regime have lived under this shadow long enough.

"They will continue to live with this grief until the general finally answers for his crimes against humanity before a court."