Alan Turing was found dead on 8 June 1954, having apparently died the day before. By his bed there was an apple, partly eaten, which contained cyanide, and it was eating this which caused his death. An inquest was held and the verdict was suicide. Some of Turing's family believed that he had taken the cyanide by accident as part of a chemical experiment. However, he had been very unhappy for some time.

Alan Turing was a gay man at a time when this was punishable by a prison sentence, and in 1952 he had been tried and found guilty. Instead of going to prison he took the option of some injections that were supposed to help 'cure' his urges. Despite his record as a brilliant scientist and key codebreaker in World War II, he was still treated as a criminal because of his personal life, and this may well have contributed to his death. In 2009 Gordon Brown, who was UK Prime Minister at that time, apologised to Turing's family.