When a shocking, plot-terminating event occurs almost halfway through The Warlock Effect, it’s not just the prospect of another 200 pages to go that alerts the reader to narrative trickery. The central character, Louis Warlock, is after all a stage illusionist who has already pulled off a seemingly impossible feat of mind-reading in front of a crowd of sceptics. Though Warlock likes to come across as a lone genius, behind his stunts lurks an invisible team of problem-crackers he dubs the Brains Trust. They include fellow magic- obsessive Dinah, a girlfriend he seems puzzlingly ambivalent about.

The West End stages and cabaret clubs of 1950s Soho are swiftly swapped for the shadowy corridors of the British secret service when Warlock is tasked with outwitting a visiting Russian mentalist. Hanikonikov has a list of British double agents hidden within a conjuror’s prop. Warlock must identify the prop and retrieve the microfilm before the spy can return to Russia. But as the mission is top secret, for once he can’t involve the Brains Trust.

And that’s just the initial set-up of this serpentine thriller. Like Sherlock Holmes, Warlock has a network of useful contacts, including magic-shop proprietors, coppers and keenly observant barmaids. But unlike Holmes, he is far from omniscient, indeed he is touchingly vulnerable. He was born Ludvik Weinschenk, a Jewish boy whose love of magic was first fostered by a trip to the Zauberkönig emporium in Berlin. Both his parents were killed by the Nazis, while he was smuggled out of Germany and sent to a spartan British boarding school. Ludvik used card tricks to win over hostile fellow pupils, and it’s been a coping strategy ever since.

Jeremy Dyson and Andy Nyman have collaborated before, on the hit play and film Ghost Stories. The former is a founder member of ‘the League of Gentlemen’, the latter a magician who has worked with Derren Brown. Their delight in the artform is showcased in a typescript, purporting to be Warlock’s own memoir, in which simple yet brilliant magic and mind-reading illusions are explained.

Warlock needs all the tricks he’s developed for his act in the occluded world of espionage, the mild terror of something going wrong on stage being only different in degree, not essence, from being unmasked as an enemy agent abroad. This not only elevates the theme of magic into something more universal – a matter of survival itself; it also becomes deeply moving. It turns out you need very little to transform horror into hope.