Foreign Secretary Margaret Beckett marked the death of former Chilean dictator Augusto Pinochet by paying tribute to the country's progress since he left office.
The 91-year-old died a week after suffering a heart attack, it was reported by the Santiago Military hospital.
Mrs Beckett said: "We note the passing of General Pinochet and want to pay tribute to the remarkable progress that Chile has made over the last 15 years as an open, stable and prosperous democracy."
Amnesty International said the death was a "wake up call" to Governments that speedy justice was needed to prevent people escaping prosecution for human rights abuses.
And it called on Chile to repeal an amnesty law that had helped protect the former dictator from prosecution.
A spokeswoman said: "General Pinochet's death should be a wake-up call for the authorities in Chile and governments everywhere, reminding them of the importance of speedy justice for human rights crimes, something Pinochet himself has now escaped.
"His death must not be the end of the story. Amnesty International urges the Chilean authorities to declare the amnesty law void and proceed with investigations and prosecutions of all those others involved in the thousands of cases of 'disappearances', torture and execution during Pinochet's period of rule.
"Families and survivors need to know what happened, need justice and need their day in court."
Baroness Thatcher was said to be "greatly saddened" by the death of Pinochet, a spokesman for the former Prime Minister said. The former British Prime Minister remained a firm and loyal supporter of Pinochet especially in the last stormy years of his life when a series of legal attempts were made in Chile to charge him with alleged crimes relating to the disappearance of thousands of dissidents during his years of power.
Lady Thatcher always maintained that Pinochet had offered the British invaluable help during the Falklands conflict of 1982.
