Behind it is a sound too shrill for human ears to acknowledge, a minatory whistle of alarm, an atavistic shriek, which goes in deeply and activates an ancient portion of the mind. ‘Strangers in camp!’ it says, summoning up the fear of the not-us, the brown or white, or mysteriously bearded, or clean-shaven, the men who smell of foods we do not recognise as wholesome: it plays on all the fictions of difference; and there are infinitely many.

Rachkovsky, I’m afraid, is an enchanter and artist too. There is no necessary moral value in telling stories. And like all artists, he doesn’t just create things from thin air. He works within a tradition he’s inherited, guided by his predecessors, but choosing when to follow them and when to make his own way. He sees what’s already there, and what has the potential to exist.

Here are the ingredients – they’re very promising: two millennia of distrust, fictions of race, a stateless people; the accusation that the Jews killed Christ, poison wells, kill Christian youths to drink their blood, or to bake it into unleavened bread. And Rachkovsky can draw on the strange and undeniable fact that many of Russia’s would-be revolutionaries are Jewish.

Rachkovsky himself has barely picked up a pen. He’s worked like the master of a Renaissance studio, supervising a team of junior craftsmen, or a surgeon who makes a few key incisions and steps back to let his underlings suture up the patient. But there is no doubt that this dark masterpiece is his. He has created a literary golem, a book that will be known as The Protocols of the Elders of Zion, that will become notorious as a warrant for genocide.

‘The Tsar himself was one of its first dupes.’

Nicholas II is taken in completely by its tale of a power-hungry Jewish elite manipulating popular discontent. He makes notes in the margins: ‘What depth of thought!’ ‘Everywhere one sees the directing and destroying hand of Judaism.’ The Metropolitan of Moscow orders extracts to be read in all of the city’s Orthodox churches.

The Tsar’s most fanatical supporters, the Union of the Russian People, an organisation of violent anti-Semites more commonly remembered as the Black Hundreds, ask the Russian government to fund the printing of the Protocols for use as propaganda.

Shortly after Nicolas arrives back in Paris, the worst pogroms in Russian history erupt across the country, inaugurating decades of bloodshed.

‘I felt obliged to do something.’

‘This is a surprise,’ says Rachkovsky, leading Nicolas into his private office. The spymaster has aged well, as plump people often do. His face is unlined and his curly hair still thick and black, though the somewhat lifeless matt texture suggests the assistance of dye.