I tried to look attentive and sympathetic – an interviewer face – but I didn’t follow what Pierce was saying. I let the silence open up, hoping he might elaborate.

‘I’ve had to pretend that the attack was real for so long, that it has begun to feel very real to me. It wasn’t really a performance, when I was talking about the book to people – I believed it. I inhabited it. So when I try to account for the lie, to trace it back to its beginning, like you keep asking me – it’s a blur.’

‘It can be very difficult to tell where an idea came from,’ I volunteered. ‘But there must have been a moment when you chose to commit to it, to write tens of thousands of words …’

‘That night,’ Pierce said. He looked exhausted. He had appeared tired earlier, in the pub, but that had disappeared during our stroll when there had been bursts of energy, and he had a brooding focus about him. That had expired, and I could see the dark crescents under his eyes, the unhealthy sheen of his face – he was starting to resemble me. How much sleep was he getting? What kind of pressure was he under?

He reared as if trying to keep himself awake, and rubbed his stubbled chin with his knuckles. ‘What I’ve realised is that it was completely improbable,’ he said. ‘Night Traffic, I mean. That kind of attack. I don’t think it happens any more. It’s incredible that people believed me. I mean, look around.’ He cast out his arm at Winterzone. The whispery, plinky music was now a cover of ‘Debaser’ by the Pixies. Amid a constellation of corporate logos, the property consortiums promised All the grit, none of the grime … Bringing London’s vibrancy to a world-class residential destination. ‘The city’s changed.’

‘People did believe you, though,’ I said. ‘So it must have been realistic.’

‘People wanted to believe,’ Pierce said. ‘But it’s mopeds now, or identity theft. Fast. Not lingering. Not personal.’

‘It does happen,’ I said. ‘It happened to me.’ Twice, I didn’t add.

‘Because it’s part of the illusion. The frisson. All these wankers playing dress-up in the ruins. Acting out a kind of city that’s gone. And the people who lived here, where are they now?’

Again, I felt the heat rising in me. ‘What, the people you want to get mugged by, as part of your Authentic Urban Experience? Fucking hell. You should take a look at yourself.’

‘Trust me, I have taken a long look at myself,’ Pierce said. ‘So we had a deal – I seem to recall that the deal involved recreating the mugging. We haven’t done that yet.’