Pocketing the knife, McNab made for the door and quietly opened it. The concrete passage was empty and he could see the fire exit ahead. He made for there, his legs screaming out from lack of use, and pushed it open to darkness and a blast of fresh air.

A quick look round and he spotted the gates as promised, lit by a street light. He forced his battered body in that direction, running like someone drunk or demented.

Scrabbling for the fence opening, he squeezed through, tearing another gash along his cheek. Then he was outside the perimeter fence.

The cocaine racing through his veins, he took a swift look left, then right, choosing the route leading to a busy road junction, knowing the sooner he hid among people, the better. At this time of night most of the shops he passed were shut, but the pubs were still open, with groups of smokers outside. McNab chose what looked like a crowded bar and, registering BrewDog Clerkenwell as the pub name, slipped inside and made straight for the Gents, getting a few odd looks on his way.

The mirror over the sink told the truth. He looked terrible and no doubt smelt worse. He splashed his battered face with cold water and headed into a cubicle. His trousers, he decided, were second in line after his face. Taking them off, he flushed the crotch in the hope it would lessen the scent of urine, while thanking God he hadn’t shat himself.

His head suddenly swimming, he sank onto the toilet seat and put his head between his knees. The cocaine rush was on the way out, he realized, and the real state of both his mind and his body was not superhuman after all.

He struggled to process what had just happened.

The Kommandant had let him go, but why? Was he really free or was he supposed to lead them somewhere or to someone? Or had they got everything they’d needed from him?

The Jock that told all.

McNab tried revisiting the scene at Leicester Square. Cleverly had definitely been nearby. He must have seen it happen. Had he told the boss? Had he even reported it to his own superiors? Or had the whole thing been prearranged?

Another thought wove its way into the puzzle. He’d arranged to meet Cleverly in the morning, but the Met detective hadn’t turned up – or had he? If he had, yet didn’t show himself, Cleverly could have followed him to the Afghan coffee shop, thus revealing where Mark Sylvester was hiding.

Christ. McNab didn’t like that particular train of thought, nor where it might lead.