One at a time the congregation came nervously up to the construct, making obeisance at every step. They stepped up the little slope of rubbish between the mechanical legs, reached into the crate and brought out a piece of paper and a sheaf of cards, checking the numbers to make sure they had them all. Then they backed quickly away and disappeared into the rubbish, returning to the city.

It seemed that there was no valedictory ceremony to this worship.

Within minutes, Yagharek and Isaac and Derkhan and Lemuel were the only organic lifeforms left in the hollow, apart from the ghastly half-living empty-headed man. The constructs remained all around them. They were quite still as the three humans shifted uneasily.

Isaac thought he saw a human figure standing on the tallest mound of rubbish in the dump, watching the proceedings, silhouetted profound black against New Crobuzon’s sepia-stained half-dark. He focused and there was nothing. They were completely alone.

He looked frowning at his companions, then moved forward towards the cadaverous figure with the pipe emerging from its head.

“Council,” he said. “Why did you tell us to come here? What do you want from us? You know of the slake-moths . . .”

“Der Grimnebulin,” the avatar interrupted. “I grow powerful, and more so daily. My computational power is unprecedented in the history of Bas-Lag, unless I have a rival in some far-off continent of which we know nothing. I am the networked total of a hundred or more calculating engines. Each feeds the others and is fed in turn. I can evaluate a problem from a thousand angles.

“Each day I read the books my congregation bring me, through my avatar’s eyes. I assimilate history and religion, thaumaturgy and science and philosophy within my data banks. Every piece of knowledge I gain enriches my calculations.

“I have spread my senses. My cables grow longer and reach further. I receive information from cameras fixed around the dump. My cables connect to them now like disembodied nerves. My congregation is dragging them slowly further out, into the city itself, to connect to its apparatuses. I have worshippers in the bowels of Parliament, who load the memories of their calculating engines onto cards and bring them to me. But this is not my city.”

Isaac’s face creased. He shook his head. “I don’t . . .” he began.

“Mine is an interstitial existence,” the avatar interrupted urgently. The man’s voice was dead of all inflexion. It was eerie and alienating. “I was born of an error, in a dead space where the citizens discard what they do not want. For every construct that is part of me there are thousands that are not. My sustenance is information. My interventions are hidden. I increase as I learn. I compute, so I am.