Postcard from Turing ‘held hidden clue’ to his suicide

TAKEN at face value, it is no more than a postcard of a religious painting sent by a holidaymaker to one of his closest friends. But the signature suggests all might not be what it seems.

The card, sent by Alan Turing to his psychologist Dr Franz Greenbaum, appears to be a coded reference to one of history’s most enduring mathematical puzzles, as well as a possible hint to his thoughts of suicide. The missive has been sold for £28,000 at auction, after auctioneers became convinced it contained a hidden message.

Rather than sending a postcard of the beaches, Turing chose an image of the illuminated cover of Antiquities of the Jews by Flavius Josephus. As Turing – who helped crack the Enigma code – undoubtedly knew, the historian was the originator of the Josephus Problem, otherwise known as the “suicide circle” or “Roman roulette”. It was inspired by first century Jewish rebels who took their own lives by lot rather than surrender to the Romans, and aims to calculate the best way of surviving.

Turing would take his own life a year after he sent the postcard, following his conviction for indecency for committing homosexual acts. He has since been given a posthumous pardon.

Dr Greenbaum’s daughter Maria Summerscale, 72, said it was impossible to know why Turing chose the card, but added: “He was a very obtuse person, wasn’t he?”