Alan Turing was one of the most remarkable mathematicians of the 20th century. He the notion that one should view a computer through the mathematical lens of a system of axioms in order to study its abilities and limitations. The Turing machine is one instance of an axiomatized computer. Turing is probably best known for cracking the German coding device "Enigma" during world war II, a feat that should have made him a national hero. However, he was given the choice between jail time and castration.
Because, you see, he was gay. And that was very uncool in Britain 60 years ago.
Turing chose castration through chemo-"therapy", and committed suicide not much after his treatment.
It is interesting to compare his life to that of Arthur Harris, or "Bomber Harris". Harris, also British, was the mastermind and chief executive behind the [Dresden bombing|http://en.wikipedia.org/wiki/Bombing_of_Dresden_in_World_War_II] in February of 1945. While there is a reasonable chance that a similar bombing today would be considered a war crime, Harris was knighted and in 1953 became a baron. In 1992, the queen-mother presided over the unveiling of a Harris statue in London. To the honor of the British people it should be noted that they did in the large not find this amusing, see the last paragraph in [1].
There is a petition under way to strike Turing's conviction from the books, see [2].