Quin pursed his lips. ‘Listen, then. As it happens, earlier today we were able to regain the signal of the police drone that, ah, went off-grid earlier this week. The Met will be pleased, it was a very costly prototype. Since then we’ve been doing some testing of its systems for them. And you should be pleased as well, because it has video footage that clears you, and anyone else, of blame for Pierce’s death.’

‘You’re such a fucking liar,’ I said, unable to withhold a laugh at Quin’s brazenness. ‘Been flying around on its own all week, has it? Recharging itself from lampposts, I suppose? Only just found it? And it just happened to be over me and Pierce, right? You’ve been using it to spy on me.’

‘We’ve had it running a variety of errands. It did look in on you. But your peregrinations have not been my highest priority. We’ve got a lot to do, preparing to roll out Tamesis nationally. We’re busy.’

An orb of rage spun in my core, throwing off instincts that went nowhere. Quin’s casual, condescending dismissal of the possibility that I might attack him only made me want to lash out all the more. But lashing out would be the sum of the act – a sordid little flash of action that would achieve zero, or worse than zero.

Instead, I sat down in one of the leather armchairs facing the desk. This made Quin smile – not a nasty patronising smile, but one of the more human expressions I had seen from him: undisguised relief.

‘Answers, then.’

‘The truth,’ I said.

He grimaced. ‘Answers.’

‘What did you want from Pierce?’

‘The truth.’

I ran my hand over my face, exasperated, abruptly tired. Sensing my annoyance, Quin cut in before I could say anything: ‘How about you tell me what Pierce told you. Your understanding of his actions.’

‘Fine,’ I said. ‘Pierce was helping you with Tamesis – you were integrating his research into your model, all that esoteric information he had collected. But you were going through the notes for Night Traffic and he became troubled. He thought you had uncovered evidence of fraud.’

I frowned, staring down at my hands, which had long stopped making fists, and were meshing together restlessly. It was hard to stay on top of which version of events was the truth.

‘So he confessed to you,’ I continued. ‘Later you told me that the confession was unprompted. You told me that you hadn’t found any evidence of fraud. That’s because there wasn’t any. He didn’t make it up. It happened as described.’

‘So it appears,’ Quin said with a nod. ‘Not what I expected, but a useful result. And it came from your work.’

Scowling past Quin’s satisfaction with this ‘result’ and the blood it had entailed, I pushed on.