GCHQ releases toughest ever puzzle in honour of Alan Turing banknote

Laura Parnaby, PA
·3-min read

GCHQ has created its toughest puzzle ever in honour of Alan Turing appearing on the new £50 note.

The Bank of England revealed the note’s design featuring the scientist and mathematician on Thursday, as GCHQ officials said their new treasure hunt involving 12 puzzles “might even have left him scratching his head”.

Mr Turing was a pioneer of modern computing and hugely instrumental in breaking the German Naval Enigma cipher in 1942, at Bletchley Park – GCHQ’s wartime home.

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Director of the cyber and intelligence agency Jeremy Fleming described him becoming the first gay man to appear on a banknote as confirming his status as “one of the most iconic LGBT+ figures in the world”.

The puzzles are based on the unique design elements of the new banknote, such as the technical drawings for the British Bombe, the machine designed by Mr Turing to break Enigma-enciphered messages.

Mr Turing’s great-nephew, James Turing, described the puzzle as a “wonderful tribute” which his family would be attempting to complete themselves.

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GCHQ officials said the full challenge could take an experienced puzzler seven hours to complete.

Colin, a GCHQ analyst and its chief puzzler, said: “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.”

New 50 pound note
Sarah John, Chief Cashier at the Bank of England, holding the new £50 note (Bank of England/PA)

On Thursday afternoon, GCHQ confirmed that some people have solved the puzzle and have been told they have the right answer.

The answers will be announced publicly in the coming weeks.

Experienced puzzler Simon Anthony, 47, told the PA news agency that he and two friends completed the puzzles together in “just under two hours”.

He said: “It’s just a very nice thing to do. The quality of the puzzles are very good and most of them are accessible. GCHQ has got an awful lot of very clever people and they could have made this monstrously hard.”

The Surrey-based YouTuber, who runs the Cracking the Cryptic channel, said the puzzles vary in difficulty with different skills needed to tackle them.

Mr Anthony continued: “It’s a nice thing to commemorate, there’s a lot of quite good messages about Alan Turing, who obviously is a war hero but he’s also a hero for nerds.

“For someone like me – I’ve been labelled a geek my whole life and it’s only been relatively recently that my geekiness has actually been an asset – someone like Alan Turing is a figure from history you can look up to.”

Mr Turing joined the Government Code & Cypher School – GCHQ’s wartime name – in 1938 to help with the code-breaking effort during the Second World War, working alongside Gordon Welchman.

In January 1952, Mr Turing was prosecuted for “indecency” over his relationship with another man in Manchester, and was given a choice between imprisonment and probation on condition of undergoing hormone treatment.

In 1954, Mr Turing took his own life.

The puzzles can be found at www.gchq.gov.uk/information/turing-challenge.