An article in The Observer Newspaper in London forty years ago today, led to the birth of Amnesty International, one of the world's leading human rights organisations.

Since the London lawyer Peter Benenson wrote that article drawing attention to two Portuguese students imprisoned for toasting freedom, Amnesty International has taken up the cause of 45,000 political prisoners and mobilises more than a million activists.

Benenson urged the public to bombard with letters all the governments known to be maltreating people imprisoned on political or religious grounds. His article in The Observer included photographs of six detainees, imprisoned for dissident opinions, in Angola, the United States, Greece, Hungary, Romania and Czechoslovakia.

With Benenson's appeal for these prisoners to be amnestied, Amnesty International was born. A driving force behind Amnesty from the start was Irishman Sean McBride, once a minister in a post-war Irish government and later a senior United Nations official. A year after it was founded, Amnesty had adopted 210 prisoners - a key rule was that no prisoner whose cause was taken up should ever have employed violence or recommended its use.

Many were obscure, unknown people, imprisoned by insecure or oppressive regimes because they dared to express ideas contrary to the governing view - other figures made world headlines. They included Soviet physicist and Nobel peace prize winner Andrei Sakharov, Czech writer Vaclav Havel, now president of the post-communist Czech Republic, Ukrainian nationalist Danylo Shumuk, discharged in 1987 after 47 years in a Soviet labour camp and Burmese democratic activist Aung Saan Suu Kyi.

Since the early 1980's U2 have supported the  campaigning of Amnesty International, at one point headlining the Conspiracy of Hope tour to promote the organisations work. If you get to see U2 on the current Elevation 2001 Tour you will find an Amnesty stand with volunteers handing out literature and explaining their work to fans.

AI has adopted the cause of 45,000 political and religious prisoners over four decades, the letter writing and - these days - electronic campaigning (see below), have pressurised governments into releasing many people from unjust imprisonment.

But the death penalty, torture, disappearances, and show trials still go on. Amnesty's million supporters still need to write letters.

To find out more about Amnesty International visit our Hearts and Minds area.

To read about Amnesty International's FAST network to stop torture, click here.