Alan Turing: Mathematician and Codebreaker, Oarsman and Runner

The face of mathematician, Alan Turing, will be on the reverse of the forthcoming £50 note. The Bank of England chose Turing after a public consultation of more than 227,000 submissions that nominated 989 different scientists. It features a 1949 quote from Turing, the father of theoretical computer science: ‘This is only a foretaste of what is to come, and only the shadow of what is going to be.’ Image: © The Governor and Company of the Bank of England.

20 August 2019

By Tim Koch

Tim Koch finds that nerds can also be athletes.

Alan Mathison Turing (1912 – 1954) fitted the work of several exceptional and long lifetimes into his single 42-year span, making significant contributions to mathematics, computer science, logic, cryptology, philosophy and theoretical biology. Most famously, his work (with others) on breaking the Nazi ‘Enigma’ and ‘Lorenz’ codes is estimated by the official historian of British Intelligence to have shortened the Second World War by two to four years, and without it the outcome of the conflict would have been uncertain. Were this not enough, Turing provided the theoretical underpinnings for the modern computer and is widely considered to be the father of theoretical computer science and of artificial intelligence, the man who produced the first model of a general-purpose computer. His signal concept of an all-purpose, stored-program computer is the basis for our digital devices today. After the war, he dabbled in quantum mechanics as well as biology, chemistry and neurology. Much of this work was related to creating machines that could learn and ‘think’, but some of it came out of his simple curiosity. In an age when deviation from what was considered the norm was little tolerated, Alan Turing was a free thinker, openly atheist and unapologetically homosexual, a man who had unconventional habits and who cared nothing for his appearance. The biographical website Alan Turing: The Enigma says:

Alan Turing did not seek to be a rebel, but (his) headmaster wrote that he was ‘the sort of boy who is bound to be a problem for any school or community.’ Throughout his life, Alan Turing was seen more as a problem to society rather than as an asset.

In Turing’s lifetime, the nation, which he more than anyone saved from Nazi domination, rewarded him with a lowly OBE, obscurity, harassment and, eventually, ‘chemical castration’. The latter was oestrogen treatment to ‘cure’ his homosexuality. It affected his body and perhaps his mind and may have contributed to his tragic and early death.

The Bletchley Park mansion, built in 1883. In 1938, Admiral Sir Hugh Sinclair, head of the Secret Intelligence Service (MI6) bought the building and 58 acres of surrounding land for £6,000 for use by MI6 and its codebreakers in the event of war. Incredibly, in a remarkable example of noblesse oblige, he paid for it himself as the Government claimed that they did not have the money.

Everything about the breaking of the enemy wartime codes remained top secret long after the war ended; peace may have been declared but the Cold War had now to be fought. Between 1939 and 1946, British codebreakers had been based at Bletchley Park, a 19th-century mansion and estate near Milton Keynes, 50 miles north-west of London. After the war, the Post Office took over the site and used it for various things including a management school. By 1990, the huts in which the codebreakers had worked were being considered for demolition and redevelopment. However, since the mid-1970s, partial accounts of Bletchley’s wartime work had emerged (though still constrained by secrecy regarding technical matters) and The Bletchley Park Trust had been formed in 1991 to maintain the site as a museum. Finally, by the mid-1990s, virtually everything was declassified, and since then this fascinating history has been studied in great detail. Today, Bletchley Park is open to the public and houses interpretive exhibits and rebuilt huts as they would have appeared during their wartime operations, as well as The National Museum of Computing which receives hundreds of thousands of visitors annually. Recently, I was one of them.

Bletchley was staffed by an eclectic mix of ‘boffins and debs’, that is, by academics and oddballs with various (often obscure) specialities and by debutantes (young, upper-class women were considered a low-security risk). During a morale-boosting visit, Churchill reportedly remarked to the operational head at Bletchley, Commander Alistair Denniston: ‘I told you to leave no stone unturned to get staff, but I had no idea you had taken me so literally’.

While touring the grounds and the huts and buildings, I came across a section dedicated to Alan Turing that included a glass case containing some of his few surviving personal effects. Displayed were some of his books, his watch, his teddy bear – and his rowing trophies.

The display case containing some of Turing’s personal effects.
Turing took up rowing when he went up to King’s College, Cambridge, in October 1931 as a mathematical scholar. Alan was first reserve in the 1934 second eight but did not row. However, he was reserve again in 1935 and got to row in the Mays when ‘5’, WM Colles, broke a foot. The blades are for King’s Second Boat in the Lent and the May Bumps of 1935.
The tankards were won by Turing for rowing in the King’s Trial Eights in 1931 (at Bow) and in 1934 (at ‘5’). He was also in the 1933 Trial Eights Boat.
Turing (back, second from the left) and the 1935 King’s Second May Boat. They bumped Downing III, Fitzwilliam House II, St Catharine’s IV and Peterhouse III. The 66kg Turing replaced the 83kg Colles but King’s II still bumped every day.

In 1959, Alan’s mother, Sara, published 300 copies of Alan M. Turing, the biography that she had written. Incredibly, she did not know of his wartime work at Bletchley Park, then still a secret. An updated centenary edition was published in 2012. The book contains a contribution by Denis Williams, a friend of Alan’s from Cambridge:

Alan Turing was a year or so my senior at Cambridge and I think it was as members of the Boat Club that we first made each other’s acquaintance. Rowing is traditionally thought of as the sport of ‘toughs’, but at that time the King’s Boat Club was an odd mixture of those born tough and of intellectuals in search of a counter-irritant. Alan’s close friends were among the intellectuals, but I believe that a sport that demands the maximum of exertion held a natural attraction for him and there was a sterling quality about him which gained respect in any company…. 

…I remember he once achieved a certain distinction by swallowing a pint (of beer) in one draught. This, he maintained, could not be done with water because the attempt made one disgusted with oneself.

In the 1930s, Germany was a popular place to go in the vacations because of the favourable terms for students. It was my good fortune to be in Alan’s company on two such excursions, once on a skiing party and once on a cycling tour. English students in Germany would often use the ‘Heil Hitler’ greeting either jokingly or as no more than the equivalent of ‘how-do-you-do?’. It was typical of Alan that he did not do so. So far as I remember he had no particular political affiliations, but he recognised the Nazi doctrine as evil and was not prepared to compromise with it by the smallest gesture…

Turing pictured in 1946.

Alan Turing was clearly not the stereotypical physically frail academic. There is even greater evidence for this when his performance in another sport, long-distance running, is examined. From In Praise of Great Men by Pat Butcher:

(Alan Turing) became a national class distance runner in his mid-thirties, when he had already made his mark as a mathematical genius. Although exceptional individuals like Turing are often drawn to physical exercise to escape their deeply intellectual work, few turn out as good at their sport as he did….

Turing had run occasionally as a schoolboy at Sherborne in Dorset in the mid-1920s. During his undergraduate years in Cambridge, he forsook running for rowing, but when he became a fellow at King’s College, he resumed running, sometimes venturing as far as Ely and back – more than 30 miles…

(The secretary of Turing’s athletics club said) “I asked him once 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’”.

Turing came close to representing Britain in the marathon at the 1948 Olympics. With three places open, he finished fifth in the qualifying race, the AAA Championships at Loughborough the previous year. His best time of two hours, forty-six minutes and three-seconds was just over eleven minutes slower than the eventual Olympic winner in an era when the marathon was far less popular than today, and when ten-minute gaps between top finishers were not uncommon.

A statue of Turing made from layers of slate by Stephen Kettle that is on display at Bletchley Park.

Turing was prosecuted in 1952 for homosexual acts. He accepted ‘treatment’ with estrogen as an alternative to prison. Despite the humiliating effects of the drug, he had no self-pity. He wrote to his friend, Norman Routledge, after his conviction:

Turing believes machines think. Turing lies with men. Therefore machines do not think.

Alan Turing died in 1954, 16 days before his 42nd birthday, from cyanide poisoning. An inquest determined his death as a suicide, but there is evidence that the poisoning was accidental. In 2013, Turing was posthumously pardoned for his conviction after a campaign to recognise him as a national hero. In 2017, legislation informally known as ‘Turing’s Law’ pardoned all gay men convicted for homosexual acts under historical legislation. In a written apology, Prime Minister Gordon Brown concluded with the words:

So on behalf of the British Government, and all those who live freely thanks to Alan’s work, I am very proud to say: we’re sorry. You deserved so much better.


  1. Thank you, Paul and John. I know that Paul is a mathematician and may be interested to know that the binary number on the £50 note converted to decimal is 23061912, Turning’s date of birth. Obvious really!

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