One try, thought Ori. He made himself sceptical. One piece of indulgence for this casualty. Only when the food was all distributed and the first homeless families were coming in from begging or thievery to doss down did Ori idle to Spiral’s side.

"Buy you a drink sometime?" Ori said. "Sounds like you and me’ve interests in common. Could chat about stuff. About doubling. About our friend Jack."

"Our friend, yes. Jack."

The man lay down in a blanket. Ori’s patience diminished. Spiral Jacobs was digging something out, a bit of paper, dirt ground into its cross of folds. He showed Ori, with a child’s grin.

It was cool when Ori walked home. He traced the route of the railway, by tracks carried over the slates on loops of brick, arches like a sea-snake. Light like gaslight or candlelight spilt from a train’s dirty windows and sent shadows convulsing over the angled roofscape to hide, darkness creeping out again from behind chimneys in the engine’s wake.

Ori walked fast with his head down and hands in pockets when he passed militia. He felt their eyes on him. They were difficult to see, their uniforms woven through with trow yarns that ate what light there was and excreted darkness. At night the clearest thing about them was their weaponry: they were armed, it seemed, at random, and in the dim he could see their batons or stingboxes, their dirks, rotating pistols.

He remembered twelve years ago, before the slump, to the Construct War, when for the first time in a century the militia tradition of covert policing-networks of spies, informants, plainclothes officers and decentralised fear-had become inadequate, and they had gone unhidden and uniformed. Ori did not remember the roots of the crisis. A child among others, with his boisterous gang he had mounted the roofs of Petty Coil and Brock Marsh on the Tar’s north shore, and watched the militia barrage the Griss Twist dumps.

With children’s aggression they had joined in the purge of the city’s constructs, the panicked hounding of the clockwork and steam-powered cleaners suddenly deemed enemy. Mobs cornered and destroyed the welded, soldered things. Most of the constructs could only stand patient while they were torn apart, their glass trod into dust, their cables ripped.

There were some few that fought. The reason for the war. Infected with viral consciousness, programmes that should not be, that had infected New Crobuzon’s constructs, the gears of their analytical engines turning in heretic combinations to spin a cold machine sentience. Thinking motors for which self-preservation was a predicate, that raised their metal, wood and pipework limbs against their erstwhile owners. Ori never saw it.

The militia had levelled Griss Twist’s jungle of trash. They shelled it, rinsing it with fire, advancing in wrecking teams through the melt and ash-scape. There had been some kind of factory there for the pernicious programmes, and it and the monstrous mind behind it were destroyed. It had been a demon or something, or a council of the aware constructs and their flesh followers.