The exact circumstances of Alan Turing's death remain a mystery to this day. A cleaner found him in his home on June 8, 1954 and an autopsy determined that he had died of cyanide poisoning. The half-eaten apple found next to his body was the presumed source of the poison although, unbelievably, it was never tested by the police. Since there were no warning signs and no suicide note left behind, the reason for his suicide baffled friends and family. When an inquest was held on June 10, the coroner stated that "'I am forced to the conclusion that this was a deliberate act. In a man of his type, one never knows what his mental processes are going to do next". He ruled that Alan Turing had committed suicide "while the balance of his mind was disturbed".
John Turing, who had attended the inquest, chose not to contest the verdict. The national press carried respectful obituaries of Turing's life and achievements and left out any mention of the 1952 conviction. Ethel Turing refused to accept the suicide verdict and maintained that her son's death had been due to his careless use of chemicals. There may actually be some truth in that considering that Turing was in the habit of running chemical experiments in his home and she had warned him in the past about accidentally poisoning himself.
There were certainly no signs of any suicidal planning either at work or at home. Many of Turing's working papers were left in disorder at the university and he had reserved time on the university's Mark II machine as usual. While he had made a new will earlier that year, there was no other sign that he was preparing to end his life. Alan Turing's body was cremated at Woking Crematorium on June 12. His mother, brother, and longtime friend, Lyn Newman, attended the ceremony. His ashes were scattered in the gardens, near where his father's ashes had been scattered years before. Despite there being no marker on the site, the city of Manchester has since constructed numerous memorials to Alan Turing in and around the city.
What reason could Alan Turing have had for suicide? Biographers have speculated that he may have killed himself due to lingering medical problems relating to the medication that he had been forced to take. Again, though, he gave no sign that any residual side effects had remained by the time of his death. There was also speculation about the possibility of blackmail or simply his increasing awareness of how his homosexuality was viewed by the government that he had helped to win World War II.
By 1950, intelligence agencies in the United States and the United Kingdom had singled out homosexuals as representing a security threat. As the Cold War intensified, a loose cannon like Alan Turing seemed unacceptable and even his informal consulting work with government agencies was ended. If anything, he was fortunate to die when he did given the massive witchhunts of the later fifties and early sixties which led to the purging of suspected homosexuals from most Western governments. Considering that much of the cryptoanalysis work that he had done was still classified, intelligence agencies would hardly have overlooked Turing for fear that he might be recruited by foreign governments (particularly the Soviet Union).
It seems ironic that the man whose groundbreaking work in mathematics and artificial intelligence should die just as the computer age was beginning. Early computers were already in existence (including a Mark II machine at the University of Manchester) and Alan Turing would certainly have been in the forefront of new technological advances as they occurred. Many of the papers that he had been working on at the time of his death were published posthumously. His name remains legendary in scientific circles and the numerous recognitions and tributes to Turing's achievements are too numerous to mention here.
As for his other legacy as a victim of the anti-gay hysteria of that era, there seems little evidence that Turing's death had any immediate impact. Despite numerous other high-profile cases and the publication of a 1957 government report recommending decriminalization, homosexuality remained a criminal offense in the United Kingdom until 1967 (1980 for Scotland and 1982 for Northern Ireland). Even with the passage of the 1967 Sexual Offenses Act, government prohibitions on certain forms of homosexual conduct remained in place for years afterward and it wasn't until 1994 that the last laws used to convict Alan Turing and Oscar Wilde were finally removed from the books. Many other countries followed suit (including most Western nations) although homosexuality remains a criminal offense in far too many countries around the world.
In addition to no longer being considered a criminal offense in most jurisdictions, homosexuality ceased to be classified as a mental disorder with the 1973 revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM). A compromise diagnosis termed ego-dystonic homosexuality persisted despite heavy criticism until finally being removed in a 1987 version of the DSM. As for the use of hormonal therapy in the treatment of convicted sex offenders, that continues to be used in cases of paraphilias (especially pedophilia). As an alternative to physical castration, hormonal treatment has shown benefit in curbing sexual recidivism although its use remains controversial.
While estrogen therapy is no longer the practice for sex offenders, specific anti-androgen agents such as cyproterone actetate (Androcur) and medroxyprogesterone acetote (Provera) remained the standard for decades. Due to frequent complaints of adverse side effects (including liver and kidney damage), leuprolide acetate (Lupron) has become the medication of choice in recent years. In addition to suppression of libido, common side effects include weight gain, lethargy, dizziness, mood swings, and, in extreme cases, loss of bone density. Despite being voluntary in many cases, court-ordered hormonal treatment is common practice in many countries across North America and Europe and is likely to continue for the forseeable future.
On September 11, 2009, U.K. Prime Minister Gordon Brown issued a formal posthumous apology to Alan Turing for the "appalling" way in which he had been treated for being gay. The apology comes in response to a petition which was signed by thousands of supporters. In welcoming the apology, gay activist Peter Tatchell said that an apology was also due to the estimated 100,000 British men who suffered similar treatment. "Singling out Turing just because he is famous is wrong".
Alan Turing would certainly have agreed.