‘When we first contacted Pierce,’ Quin said, ‘one of the things we were trying to understand was crime. Street crime, burglaries. Tamesis already uses all available police and Home Office reporting and statistics to inform users about crime rates, but it’s very patchy. There’s a psychological dimension that’s all-important and governs how users behave. Call it fear, but that’s not all that it is. And it shapes user decisions: where they go, when, alone or in company. Where they live. And that feeds back into the city. It affects rents and house prices. A street is ill-used at night, so it makes people nervous, they avoid it and it stays little-used. Crime might even rise as the number of possible witnesses falls. Fear isn’t always the result of crime – it can cause crime.

‘Pierce offered a fascinating case study. He was independently building his own map of the city, one of reputation and myth, precisely what our data lacked. And he had, in Night Traffic, written a masterful account of urban fear, of the rippling consequences of a single violent crime. Then he said he had been lying about everything. Infuriating. But, you know, when life gives you lemons, update your seasonal produce model and short-sell Del Monte. Do you know why I built Tamesis, Jack?’

I shook my head. There were all sorts of plausible, reasonable answers I could have given – or insulting ones – but he was just setting up his own, not asking for mine. Let him get on with it.

‘No nefarious agenda – it’s what I’ve always said. To bring people together. To create chance encounters, to synthesise social capital, to make innovation and collaboration happen. Because it works. Bringing you and Pierce together – a real leap forward.’

A zigzag of fingers on the phone screen, and the God Board returned to what it had been when I walked in, the busy real-time overview of the Friday night city.

‘What do you see?’

This time he did want an answer to his question.

‘London.’

‘Sure. But, this is not a pipe. This is data, the readouts. It’s a dashboard. What’s the real city?’

‘Outside,’ I said. ‘Buildings. People.’ I rolled my eyes. ‘The friends we made along the way. Love. The adventure in the heart of a child. I don’t fucking know. You sound just like Pierce, with his fucking riddles. Just tell me.’

‘Pierce did have some compatible lines of thought,’ Quin said. He was unperturbed by my reluctance to cooperate. ‘But you were right, about buildings and people, not the friends shit. Buildings and people are the hardware, or the hardware and the users if you want to go on believing in free will. Really it’s all hardware. There’s also software – the information governing the environment, the rules and laws, the socioeconomic structures. And the information is as important as the physical fabric. Maybe more so. You rent, right?’

‘Used to.’