Dr Alan Mathison Turing

View certificate of service

FO Civilian, TSAO
Summary of service
Bletchley Park September 1939 - December 1942. Cottage, Enigma Research. Head of Hut 8, design of Bombe, with Welchman and Keen. USA December 1942 - January 1943, on voice decryption research. Hanslope Park January 1943 - 1944.
Cambridge - King's College; Princeton.
Published references
Hodges (1983); Copeland (2004); Turing (2015)
Online obituaries
The Times (on St Andrews University, History of Maths Archive)
Other information
Appointed OBE in 1945 for his wartime service. Elected as a Fellow of the Royal Society in 1951. Inducted into the NSA Hall of Honor in 2014.
Alan Turing 1912 - 1954

Alan Turing will always be associated with the birth of the digital computer age. Using his deep understanding of mathematics, he developed statistical approaches to codebreaking at Bletchley Park. His belief in a machine approach was soon vindicated by the operation of his ‘bombe’. ‘The Prof’ was held in high regard there despite his sometimes shabby, uncouth appearance, and strange behaviour.

Alan Turing was born on 23 June 1912 in London. At Sherborne he studied aspects of science – largely self-taught – but took little other interest in school life. His untidy habits and shy, hesitant, high pitched voice were to remain with him, as would his ability to think deeply, working from first principles. He seemed an anti-social loner, but with a sense of humour. He was much happier at Kings, Cambridge, both because of the intellectual challenge and the tolerance of his homosexuality. He became a Fellow in 1935, and pursued his interest in mathematical logic. In his paper of 1936 ‘On computable numbers…’ he proposed a machine that could perform logical operations, seen as the underlying foundation of digital computation.

Turing had long been interested in codes, so when he arrived at Bletchley Park on 4 September 1939, he was assigned to the Enigma Research section under Dilly Knox who soon reported that Alan Turing was producing a stream of ideas. Turing designed a machine for breaking Enigma, the ‘Turing bombe’ which was operating to help break Enigma messages by the autumn of 1940.

By December 1939 Turing had worked out the way the Germans chose their Naval Enigma message ‘indicators’. He led the small Naval Enigma team in Hut 8, and soon he was being consulted from around the site. After thinking deeply about a cryptographic problem, he could often suggest an approach that would open up a successful solution. In June 1940 Turing produced a cryptanalytic reference manual known in Bletchley Park as ‘Prof’s Book’.

Hut 8 steadily worked towards the breaking of Naval Enigma, and, after receiving captured material, they succeed in the summer of 1941, breaking the vital Atlantic waters surface ship key, Dolphin, virtually every day. Turing’s method for reducing the number of possible wheel orders, ‘Banburismus’, was based on his development in sequential statistical analysis, an original contribution to mathematics. Turing had no interest in administration, so Hugh Alexander was transferred to Hut 8 in March 1941, soon becoming head of the Hut. Turing developed a statistical approach to breaking the Fish codes, called ‘Turingery’ in the Testery; those used on the machinery in the Newmanry were a derivative of this approach. He was not directly involved in the development of their machines, such as Colossus, but the concept certainly stemmed from his discussions with Max Newman.

In December 1942 Turing left for the USA, to help with the US high-speed bombes, and a system of secure voice radio at Bell Labs. He returned home in August 1943, leaving Bletchley Park for Hanslope Park to build an elegant secure voice communications system. After the war, Turing went to NPL to build the computer, ACE. He produced a visionary design but was frustrated by the slow progress. Max Newman invited Turing to the Computing Laboratory at Manchester University in the October 1948. He designed an arithmetic routine for the Baby (June 1948) and used the machines there for a variety of pioneering applications, such as artificial intelligence, a theory of growth in biology, and for modelling reactions. He was made an FRS in 1951. Turing died of cyanide poisoning in June 1954; the coroner recorded a verdict of suicide.