The Mathematician Who Broke Enigma, Was Chemically Castrated by His Own Government, and Died Beside a Half-Eaten Apple

Alan Turing (1912–1954) had been the senior cryptanalytic mathematician at the Government Code and Cypher School at Bletchley Park from September 1939. His 1939–1940 design of the electromechanical Bombe — the machine that mechanised the search for daily Enigma rotor settings — is the single largest individual contribution to the wartime Allied signals-intelligence effort. The Bombes broke approximately 84,000 German Enigma messages per month at peak. Estimates of war duration shortened by Bletchley’s output range from two to four years.

Turing’s work was classified at the highest level for the rest of his life and for several decades after. He returned in 1945 to academic mathematics at Manchester and to his 1936 work on what would become the theoretical foundation of computing.

March 1952

In December 1951 Turing began a relationship with a 19-year-old Manchester man named Arnold Murray. Murray’s accomplice burgled Turing’s home in January 1952. Turing reported the burglary to the Manchester police. The police interview produced an admission of the sexual relationship with Murray. Homosexual acts between men were a criminal offence in England under the Criminal Law Amendment Act 1885.

Turing was charged with gross indecency at Manchester Crown Court on 31 March 1952. He pleaded guilty. The court offered him a choice: two years in prison, or chemical castration through hormonal therapy with synthetic oestrogen for twelve months. He chose the oestrogen.

The treatment produced gynaecomastia, weight gain, depression, and impotence. He lost his security clearance and his consulting work for GCHQ. His passport was restricted; he was barred from the United States.

8 June 1954

His housekeeper found him dead at 8 Adlington Road, Wilmslow, on the morning of 8 June 1954. The post-mortem identified cyanide poisoning. A half-eaten apple lay on the bedside table. The apple was not chemically tested at the time. The inquest verdict on 10 June 1954 was suicide.

Andrew Hodges’s 1983 biography argues for suicide on the available evidence. Turing’s mother and brother argued for accidental death — he had been electroplating spoons with a homemade potassium-cyanide solution in his spare bedroom and might have ingested residue. Either reading is consistent with the physical evidence.

The half-eaten apple did not appear in the inquest verdict but became the central icon of the case. The Apple Computer logo is an apple with a bite taken out; the company has consistently denied that the logo references Turing.

2013

The British government formally apologised in September 2009 (Gordon Brown). Queen Elizabeth II granted a posthumous royal pardon on 24 December 2013. The 2017 Alan Turing Law (formally the Policing and Crime Act 2017, Section 164) extended automatic pardons to all British men convicted under historical anti-homosexuality statutes.

Approximately 49,000 men received posthumous pardons under the 2017 statute. Turing’s name is on the £50 note from 23 June 2021 — the anniversary of his birth.