This is adapted from an article Road breaker by P Butcher in the magazine Runner's World(September, 1999), 56-57.
Alan Turing ran a little while he was at Sherbourne school, usually when football was cancelled because of bad weather. He did not run while an undergraduate at Cambridge, preferring to row, but once he had won his fellowship to King's College he began to run more seriously, his frequent route being from Cambridge to Ely and back, a distance of around 50 km. He did a little running while at Bletchley but only when he moved to the National Physical Laboratory did he take up running more seriously. J F Harding was the secretary of Walton Athletic Club at this time and he recalls first meeting Turing out on a run:-

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.
Looking back, he was the typical absent-minded professor. He looked different to the rest of the lads; he was rather untidily dressed, good quality clothes mind, but no creases in them; he used a tie to hold his trousers up; if he wore a necktie, it was never knotted properly; and he had hair that just stuck up at the back. He was very popular with the boys, but he wasn't one of them. He was a strange character, a very reserved sort, but he mixed in with everyone quite well: he was even a member of our committee.
We had no idea what he did, and what a great man he was. We didn't realise it until all the Enigma business came out. We didn't even know where he worked until he asked us if Walton would have a match with the NPL. It was the first time I'd been in the grounds. Another time, we went on our first ever foreign trip to Nijmegen in Holland he couldn't come, but he gave me five pounds, which was a lot of money in those days, and said 'Buy the boys a drink for me'.
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; its the only way I can get some release.'

Turing came fifth in the AAA marathon which was used as a qualifying event for the 1949 Olympic games. His time was 2 hours 46.03 minutes which by modern marathon times does not look so great but was good at that time. To put it in perspective, the winning Olympic time was only 10 minutes better at the 1948 Olympics. A leg injury put an end to further serious running by Turing. However, even after he moved to Manchester he still occasionally represented Walton in events. The last event he ran for the club was in April 1950 when he was on the Walton relay team in the London to Brighton race. Also a member of the same Walton team was Chris Chataway, who a few years later went on to help Roger Bannister break the four minute mile.
P Butcher