The Tsar resists the pleas of his aides, urging him to hurry away. He is conscious of a duty to show courage. He moves with a regal hauteur. First, he attempts to console the dying men. There’s nothing to be done, the wounds are clearly mortal. Then he goes over to take a long look at his would-be assassin. Rysakov is a member of a revolutionary cell called Narodnaya Volya, People’s Will, who are nothing if not determined. As far as the revolutionaries are concerned, the Tsar is a sinister tyrant in blood-stained robes, leading a filthy, backward slave empire. That’s easy enough to grasp. The world will clearly be a better place without him. Over the last few years, they have mined Odessa harbour to destroy the Tsar’s boat, tried to set bombs under the Royal Train on its way back from the Black Sea, and blown up part of the Winter Palace. They’ve failed repeatedly and now the secret police are on to them. This was a last desperate attempt.

Colonel Dvorzhitsky’s hand hovers over the royal arm, eager to spirit the Tsar away. Alexander examines the revolutionary with a kingly contempt. Rysakov, in spite of his grounding in progressive political theory, is overcome with awe and cannot meet the monarch’s eyes. The truth is, he’s a little rattled by the sight of blood. The butcher’s boy is dying loudly and messily.

There’s something about human pain that rightly shakes our confidence in stories. It was supposed to work like this: a cruel tyrant lying dead, joyful citizens pulling down statues of the despot. But in the forlorn stories that we know in our hearts to be truer, good and evil are more hopelessly mixed.

This doesn’t feel any nearer to Utopia. There’s just a young boy crying out in pain for his mother, panic, injured horses, and the smell of blood. Even the broken Cossack, so martial in life, the incarnation of Orthodox prowess, draws our sympathy.

And then the second bomb goes off.

Rysakov set out today with three accomplices. The second lost his nerve. But this third one, Hryniewiecki, was standing by a railing just a few yards from the Tsar. At the point when Alexander was about to leave, he threw his bomb. The blast has removed both Alexander’s legs below the knee. Even now, he could still survive if someone has the presence of mind to stem the bleeding: apply a tourniquet, put pressure on the femoral artery – just raising his shattered legs would help. But no one does. There’s general panic. They can’t get him into the carriage so they put him in an open sleigh, which leaves a trail of blood in the slush as it carries him dying to the Winter Palace.

The canopy preserves the spot on the embankment where the Tsar fell.

‘I visited Russia at least twice a year.’