‘Then it’s over. Keep in touch.’

The white screen reverted back to its countdown, and the background noise from Grant’s microphone fell silent. The meeting was over, and not a moment too soon. Pearce wasted no time in heading to the door, and Roth caught the man’s eyes gazing forlornly at the bin as he passed it.

‘Right,’ said Roth, grabbing the forensic bag in one hand and stuffing it back into his rucksack, ‘it’s been a lovely morning, but I need some sleep. Wake me up when something interesting happens.’

‘Oliver,’ said Marshall, ‘a word, please.’

‘Twat. That’s a word.’

‘Out in the corridor, now.’

Roth rose to his feet and laughed.

‘Why not in here? Because you’re afraid Nick’s still listening? And hi Nick, if you are.’

Marshall didn’t say another word. He walked to the door, grabbing Roth by the shoulder as he passed – tight enough to show his impatience but not tight enough to make it seem aggressive. He took Roth out of the office, found an empty stretch of corridor, and stood him against the wall.

‘Sadism, severed heads and cavalier bad judgement. Not cool, Oliver.’

‘Do you have any idea how much I cringe when an adult tries to use the word “cool”?’

‘My language is not the problem here, Oliver. An experienced war veteran is giving you combat advice, and you should bloody well listen to it.’

‘Go on then. Advise me.’

‘However much you hate an enemy, you can’t veer from your military training. That’s how they win. Even if you despise them with all the passion in your whole being, you still dispatch them with tactical cunning and ruthless rationality. What you don’t do is give in to mindless impulses which tell you to indulge in sadism and self-entertainment, like carving off a dead enemy’s head just for a trophy.’

Marshall took a step back. Until then, Roth had neither noticed nor cared how close Marshall had been to his face. His boss’ words had been predictable: Roth had spent many meetings listening to Marshall’s lectures about logical approaches and strategic brutality. But brutality wrapped in logic was still brutality, and Roth felt that his personal investment in his work added to his effectiveness rather than dulled it.

‘The younger version of you used to know all that,’ Marshall continued. ‘This last year, you’ve started to lose the sensible, measured determination I used to admire in you. You’re on dangerous ground, and you can’t even blame it on puberty hitting you like a tonne of bricks. This—’

‘No, I can’t,’ Roth interrupted. ‘I’m blaming it on you.’

While Marshall took time to react, Roth took the opportunity to steal the initiative.