But there was courage in his ‘literal-mindedness’ too. Turing never hid his homosexuality. Leavitt suggests that, as a logician, ‘he simply accepted it and assumed (wrongly) that others would as well’. It’s difficult to believe. It makes his character at odds with his unfettered, almost whimsical approach to mathematical problems and the sharpness of his letters to his mother that Leavitt quotes. Throughout The Man Who Knew Too Much there is a mischievous, bloody- minded, somewhat smug and loveless figure stumbling forward.

Turing’s final years are a disgusting indictment of something, though I can’t quite fix on what. Our judiciary? Our sexual f***ed-upness? The whole of postwar Britain? In 1952 Turing was arrested for ‘gross indecency’ with another man and sentenced to submit to a course of oestrogen treatments — chemical castration — to ‘cure’ him of his homosexuality. He grew breasts. Two years later, humiliated and mad, the man who devoted so much time to protecting his people and hastening the end of the war, committed suicide by eating an apple dipped in cyanide.

Leavitt’s own conclusion is nicely done, and with a mildness I can’t share after reading The Man Who Knew Too Much. I feel sick. But Leavitt manages to see something past this visceral response.

Perhaps what chills us is that in taking his own life Turing actually chose to camp it up a bit... yet in all the pages I have read about Turing — and there are scores of them — no one has yet mentioned what seems to me the most obvious message. In the fairytale the apple into which Snow White bites doesn’t kill her; it puts her to sleep until the Prince wakes her up with a kiss.


Alexander Masters’s Stuart: A Life Backwards was awarded the Hawthornden Prize last week.

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