GCHQ sets ‘Turing challenge’ to honour wartime code-breaker with seven-hour puzzle

‘Alan Turing has inspired many recruits over the years’

GCHQ has set its toughest puzzle to celebrate the appearance on the Bank of England’s new £50 note of Alan Turing, whose team broke the German Enigma code during the Second World War.

Intelligence staff have put together a dozen puzzles based on the unique design elements of the new note, such as the “British bombe”, the machine used to decipher Enigma at Bletchley Park, the service’s headquarters at the time.

The Turing Challenge is part of a regular series of puzzles from GCHQ to illustrate the analytical skills needed in deciphering secrets. The one produced for the banknote, it says, will take an experienced puzzle user about seven hours to solve.

Turing will be the first openly gay man to have his face on a banknote. The brilliant mathematician, considered to be one of the founding fathers of computing and a pioneer of artificial intelligence, was convicted of a criminal offence when homosexuality was illegal. He was forced to accept chemical castration as an alternative to imprisonment

Colin, a GCHQ analyst and its chief puzzler, who does not want his full name published for security reasons, says Turing’s intelligence achievements have attracted young people to the service.

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He says: “Alan Turing has inspired many recruits over the years to join GCHQ, eager to use their own problem-solving skills to help to keep the country safe.

“So it seemed only fitting to gather a mix of minds from across our missions to devise a seriously tough puzzle to honour his commemoration on the new £50 note. It might even have left him scratching his head – although we very much doubt it!” 

Jeremy Fleming, GCHQ Director, said: “Alan Turing’s appearance on the £50 note is a landmark moment in our history.

“Not only is it a celebration of his scientific genius which helped to shorten the war and influence the technology we still use today, it also confirms his status as one of the most iconic LGBT+ figures in the world. 

“Turing was embraced for his brilliance and persecuted for being gay. His legacy is a reminder of the value of embracing all aspects of diversity but also the work we still need to do to become truly inclusive.”