For their day-to-day duties they relied on their reputation and on their vast network of informers—rewards for information were generous—and plain-clothed officers. When the militia struck, it was the man drinking cassis in the café, the old woman weighed down with bags, the clerk in stiff collar and polished shoes who suddenly reached over their heads and pulled hoods from invisible folds in the cloth, who slipped enormous flintlocks from hidden holsters and poured into criminal dens. When a cutpurse ran from a shouting victim, it might be a portly man with a bushy moustache (palpably false, everyone would reflect afterwards, why had they not noticed that before?) who would grab the offender in a punishing necklock and disappear with him or her into the crowd, or a militia tower.

And afterwards, no witness could say for sure what those agents had looked like in their civilian guise. And no one would ever see the clerk or the portly man or any of them again, in that part of the city.

It was policing by decentralized fear.

It had been four in the morning when the prostitute and her client had been found in Brock Marsh. The two men walking the dark alleys with their hands in their pockets and their heads jaunty had paused, seeing the crumpled shape in the dim gaslight. Their demeanour had changed. They had looked about them, then trotted into the cul-de-sac.

They found the stupefied pair lying across each other, their eyes glazed and vacant, their breath ragged and smelling of cloying citrus. The man’s trousers and pants were dropped around his ankles, exposing his shrivelled penis. The woman’s clothes—her skirt complete with the surreptitious slit many prostitutes used to finish their work quickly—were intact. When the newcomers had failed to wake them, one man had remained with the mute bodies and the other had run off into the darkness. Both men had pulled dark hoods over their heads.

Some while later a black carriage had pulled up, drawn by two enormous horses, Remade with horns and fangs that glinted with slaver. A small corps of uniformed militia had leapt to the ground and, without words, had pulled the comatose victims into the darkness of the cab, which had sped off towards the Spike that towered over the centre of the city.

The two men remained behind. They waited until the carriage had disappeared over the cobbles of the labyrinthine quarter. Then they looked about them carefully, taking stock of the sparse harvest of lights that glinted from the backs of buildings and outhouses, from behind crumbling walls and through the thin fingers of fruit trees in gardens. Satisfied that they were unobserved, they slipped off their hoods and thrust their hands back into their pockets. They melted suddenly into a different character, laughing quietly with each other and chatting urbanely as, innocuous again, they resumed their graveyard-shift patrol.