Alan Turing (1912 – 1954)
Mathematician, cryptanalyst and former resident of Guildford
‘In a short life he accomplished much, and to the roll of great names in the history of his particular studies added his own.‘
So is described one of the greatest figures of the twentieth century, yet Alan Turing’s name was not widely recognised until his contribution to the breaking of the German Enigma encoder became public in the 1970s. The story of Turing’s life fascinates and in the years since his suicide, Turing’s reputation has only grown, as his contributions to logic, mathematics, computing, artificial intelligence and computational biology have become better appreciated.
Alan Turing (1912-1954), OBE, FRS, has been described as the father of the modern computer. His life’s work had an immense impact on the history of the 20th century, both in breaking the German ‘Enigma’ encoder in World War II, and in laying the foundations of computer science. However, Turing was judicially persecuted for his homosexuality, which probably led to his suicide two years later.
Turing was the second son of an Indian colonial family, who later settled in Ennismore Avenue, Guildford. Turing attended Sherborne School in Dorset, where he shared classes with John Halliley, who would later become known as actor John le Mesurier. He also met Christopher Morcom, who was his first love (although their relationship appears to have remained platonic). They had a shared interest in science and mathematics. Morcom tragically died in 1930, which may have encouraged Turing’s academic studies so that he could complete the work Morcom had not been able to do.
Turing was accepted into Kings College Cambridge, graduating in 1934, and was elected a fellow. In 1936 he published ‘On computable numbers’ which introduced the idea of a machine (the ‘Turing machine’) which might be capable of making any mathematically imaginable computation. Turing perceived that such a machine could be ‘universal’, that is, it could theoretically replace any other machine.
Time spent in Guildford
Alan Turing’s parents lived at 8 (now renumbered as 22) Ennismore Avenue, Guildford following his father’s retirement in 1927. Although away at school for long periods, Guildford gave Alan his first proper home and the family would go for long walks in Stoke Park and on the North Downs. Alan developed an interest in astronomy and from his Guildford home he spent hours star gazing and drawing the night sky. Alan continued to visit the family home whilst he was at university.
Alan Turing’s brother, John, married Joan Humphreys at Stoke Church, Guildford on 25 August 1934. The ceremony was witnessed by their father, Julius, and reported in the local Surrey Advertiser newspaper. John and Joan moved to a house in Jenner Road, Guildford where they raised their family. Alan visited them and would delight his nieces by solving cracker puzzles at Christmas.
Alan’s parents separated at the beginning of the war. His father, Julius, relocated to London whilst his mother, Ethel, initially moved to Epsom Road and then 3 South Hill, following her husband’s death in 1947. Alan visited his mother there and she recalls in his biography that they spent many hours wandering around Guildford together talking about his work projects. Alan’s last visit to Guildford was for Christmas 1953, six months before his death.
Probably Turing’s most famous achievement was his contribution to the breaking of the Enigma, the encoder used by the Germans to encrypt secret messages during the Second World War. In March 1940 Turing’s device, later known as the Turing Welchman Bombe, came into operation at Bletchley Park. The Bombe, a series of electromechanically driven rotors, used fragments of decoded Enigma text (‘crib’) to calculate any matching setting of the corresponding rotors in the Enigma encoder, which were used to scramble the messages. The Bombe was an ingenious logic engine, designed to short circuit on any calculation contradicting the ‘crib’, thus freeing computational power to check further settings.
In 1945, Turing was awarded an OBE for his war work, which also included a secure voice communications machine (‘Delilah’). He also began work at the Maths department of the National Physical Laboratory in Teddington. During this time he lodged in Hampton, but spent a lot of time in Surrey.
In 1948, Alan began work at the Computing Laboratory at Manchester University. His work included research on the earliest stored-program computers, definitions of ‘artificial intelligence’ (the ‘Turing Test’) and mathematical biology.
He regularly visited his mother (his father died in 1947), and she writes in his biography that they spent many hours wandering around Guildford together talking about his projects.
Turing was also a keen athlete, and was known to run in Guildford, Westcott and Leith Hill. He often ran the 18 miles between his home in Hampton and his mother’s house in Guildford. He was a member of the Walton Athletics Club, and was a world-class marathon runner, coming fifth in the trials for the 1948 Olympics. One member remembers him joining the club:
‘We heard him rather than saw him. He made a terrible grunting noise when he was running, but before we could say anything to him, he was past us like a shot out of a gun. A couple of nights later, we kept up with him long enough for me to ask him who he ran for. When he said nobody, we invited him to join Walton. He did and immediately became our best runner.’ – J.F. Harding
Harding also remembers:
‘I asked him one day why he punished himself so much in training. He told me “I have such a stressful job that the only way I can get it out of my mind is by running hard; it’s the only way I can get some release.’
Homosexuality and treatment
Although shy, Alan did not conceal his homosexuality from his friends. Whilst at Bletchley Park, he became engaged to Joan Clark, a fellow code breaker. Joan knew Alan was gay and although they got on well Alan felt that the situation would be unfair on them both and so broke off their engagement.
Tragically, Turing’s short affair with 19 year old Arnold Murray in 1952 brought his private life into conflict with the society of his day. Discovering that Murray was an accomplice to a burglary of his house, Turing reported him to the police, making a full statement on their relationship. Both Turing and Murray were prosecuted for homosexual acts, then illegal whether in private or in public, under section 11 of the Criminal Law Amendment Act 1885. Turing had been unashamed in his admission, although he wrongly believed that the law was about to change (it would not until 1967). Although the law was an old one, a chemical hormonal ‘treatment’ programme as an alternative to punishment by imprisonment was new in the early 1950s. Turing submitted to the treatment (and its unpleasant side effects), probably in order to be able to pursue his work, although his criminalisation brought worries about his employment and barred his entry to the USA.
Suicide and apology
Alan left no suicide note before eating an apple apparently laced with cyanide. The apple was never tested and his mother never accepted the coroner’s verdict of suicide. His motivation is unknown, but the humiliation he had received by the prosecution, along with the cruel effects of hormone treatment, seem likely to have influenced his state of mind. On the 12 June 1954, Alan was cremated at Woking Crematorium, St John’s, and his ashes scattered where those of his father had been. He has been memorialised elsewhere, including at Sackville Memorial Park, Manchester, and the University of Surrey, Guildford.
In September 2009 Prime Minister Gordon Brown issued a formal apology on behalf of the British Government for Turing’s treatment, recognising his contribution to the war, saying ‘he deserved better’.
“Sometimes it is the people no one can imagine anything of who do the things no one can imagine.” – Alan Turing
Turing is an LGBTQ+ history icon.
Alan M. Turing by Sara Turing (Cambridge University Press), 2012.
To commemorate the centenary of Turing’s birth, this re-publication of his mother’s biography contains a new foreword by Martin Davis and a never-before-published memoir by Alan’s brother. The book sheds new light both on Turing and his relationship with his family.
Alan Turing: the enigma of intelligence by Andrew Hodges (Unwin), 1985
Fellow-mathematician and gay activist Andrew Hodges, celebrates Turing’s achievements and explores his character throughout his life.
All publications are available at Surrey History Centre as part of the Local Studies library collection.
The Alan Turing website www.turing.org.uk
Created and maintained by Andrew Hodges, this website gives a detailed biography of Alan Turing, as well as a scrapbook of photos and documents relating to him.
The Turing Digital Archive www.turingarchive.org
This website contains nearly 3,000 images of letters, photographs, newspaper articles, and unpublished papers by or about Alan Turing. The images were scanned from the collection of Turing papers held in the Archive Centre at King’s College, Cambridge.
Pink Triangle Theatre https://en-gb.facebook.com/pg/PTTUK/about/
For the Turing centenary in 2012, Pink Triangle Theatre made a short film about a letter written to Alan Turing by a schoolboy.
On BBC iplayer you can listen to Witness: The Death of Alan Turing at http://www.bbc.co.uk/programmes/p01zymxx and discover more about the man behind Enigma at http://www.bbc.co.uk/news/magazine-27701207
For an article about Turing’s connections with Guildford see The Guildford Dragon
Click here to read about Alan Turing and Bletchley Park on the Historic England Pride of Place project website https://historicengland.org.uk/research/inclusive-heritage/lgbtq-heritage-project/
Guildford Town Guides organise a walk, where you will hear about Alan Turing and Guildford. For more details, visit http://www.guildfordwalks.org.uk/walkAlanTuring.php