Lord Browne-Wilkinson ruled on Thursday that the previous Law Lords' decision not to uphold General Pinochet's claim of sovereign immunity was invalid.

He led a panel of five Law Lords, who unanimously agreed that the links of one of the earlier lords with Amnesty International meant their verdict could not stand.

Lord Irvine: Stop this happening again

Lord Irvine wrote to Lord Browne-Wilkinson on Wednesday saying checks had to be put in place to stop future conflicts of interest.

The letter said: "We must make every effort to ensure that such a state of affairs could not occur again.

"My request to you, therefore, as the senior Law Lord, is that you, or the Law Lord in the chair, ensure at the time when any committee is being composed to hear an appeal, that its proposed members consider together whether any of their number might appear to be subject to a conflict of interest; and in order to ensure the impartiality, and the appearance of impartiality, of the committee, require any Law Lord to disclose any such circumstances to the parties, and not sit if any party objects and the committee so determines."

General Pinochet's lawyers won their case to quash the original verdict

Following the initial Law Lords' ruling that the extradition process against General Pinochet should proceed, it emerged one of the panel who heard the case had links with a human rights group.

Lord Hoffmann - who cast the final and decisive vote in the 3-2 verdict in the case - is the director of Amnesty International's charitable arm and his wife has worked for the organisation itself for 20 years.