Electronic locks held shut all the exits from the stairwell, but on the fifth floor the door was propped open, despite red signs warning to check in with security and have BunkMate identification ready. What kept the door from closing was a stack of copies of the magazine I worked for. Used to work for. This topmost floor had fewer desks than the others, and they all pointed the same way. Half the space was given over to clutches of mismatched stools, benches and bean bags, surrounding a low dais on three sides. Behind the dais, filling an immense expanse of warehouse wall, was a map.

Quin called it the ‘God Board’. We had been forbidden to photograph it when the magazine came to visit – or rather, it had been temporarily switched over to show an innocuous Tamesis interface. But tonight the God Board was in God mode, showing the seething hive of London. Thousands of symbols and icons crawled and pulsed across its heat-marbled surface – individual Tamesis users, on their way home, out for dinner, going to clubs. Buses, taxis, Tube and trains, even emergency vehicles, all had their own symbols, and information overlays slid and flickered, showing traffic speed, user density and other metrics I couldn’t guess at. Jittering data scrolled at the edges of the map, arcane readings of Tamesis performance, presumably critical to its operators: system latency, request response speed, average social velocity, T-link completion. Just as with Pierce’s wall-map, the bombardment of information was at first overwhelming, and I had to pause and take it in. But it was possible to skim meaning off the surface of this deep, churning well of data. The city was visibly cooling, the T icons trekking outwards and coming to rest. London was going to sleep.

What would it be like in here in a few hours, when it began to wake up? Just imagining it gave me a pop of serotonin.

The room had changed in the months since I was last allowed in. The God Board had been moved to one side, and a second screen of equal size now stood beside it. This showed the entire British Isles, and while the London screen fizzed with information, the new map was cool and grey and empty. Waiting. There was only one readout that was not resting at zero: a countdown, ticking towards a couple of weeks in the future.

‘He’s waiting for you,’ a voice said from the ranks of desks. I had registered that I was not alone – about a third of the desks were occupied. But none of the workers sitting there had so much as glanced at me when I entered. They were lost in communion with Tamesis, suckling on map-glow.