Now, clearing a hostile building is really a game for three or more players. Six is a good number. The player to the left of the dealer checks the rooms, with two more as understudies, while the other three watch the corridor. That’s how it works. If you really must play it on your own, the rules are entirely different. You open every door very slowly, checking your back as you do it, squinting through the hinges and taking about an hour to cover ten yards of corridor. That’s what it says in every manual ever written on the subject.

My feeling about manuals is that the other fellow’s probably read them too.

I zig-zagged down the corridor as fast as I could go, gun outstretched, flinging open all seven of the doors until I reached the other end where I threw myself down beneath the window, braced to empty the magazine at anyone who might pop their head out. Nobody did.

But now the doors were open, and the first one on the left led on to a staircase. I could see a few feet of banister, and above it, a mirror. I got up into a crouch and ran through the door, waving the gun up and down the stairs in as threatening a fashion as I could manage. Nothing.

I drew back my right hand and drove the butt of the Glock into the middle of the mirror, shattering the glass. I picked out a hefty-looking piece and cut my left hand on it. Which was an accident, in case you’re wondering.

I held up the broken mirror and squinted at the reflection of my chin. The wound was less than pretty.

Back in the corridor, I reverted to the slow method of clearance, creeping to the edge of each door-frame, sticking the mirror out across the doorway, turning its gaze slowly across the room. It was a clumsy method, and since the walls were no more than an inch of Gyproc plaster board, and probably couldn’t have stopped a cherry-stone squeezed from the fingers of a tired three-year-old, it was also fairly useless. But it felt better than standing in the doorway shouting ‘yoohoo?’

The first two rooms were in the same state as the corridor. Dirty, and piled with junk. Dead typewriters, telephones, three-legged chairs. I was reflecting on the fact that there is nothing in any of the world’s great museums that looks quite as ancient as a ten-year-old photocopier, when I heard a noise. A human noise. A groan.

I waited. It didn’t repeat, so I replayed the noise in my head. It was the next room down the corridor. It was male. It was someone having sex, or in a bad state. Or it was a trap

I eased back out into the corridor and along to the next doorway, and lay down along the wall. I pushed the mirror out in front of me and adjusted its position. Sitting in a chair in the middle of the room, his head slumped forward on to his chest, was a man. Short, fat, middle-aged, and tied to the chair. With leather straps.

There was blood on the front of his shirt. A lot of it.

If it was a trap, this was the moment when the opposition would expect me to leap up and say, ‘good heavens, may I be of any assistance?’. So I stayed where I was and watched. The man and the corridor.

He didn’t make any other noise, and the corridor didn’t do anything that corridors don’t normally do. After a solid minute of watching, I tossed the mirror aside and crawled round the door-jamb into the room.

I think maybe I’d known it was Woolf, from the moment I first heard the moan. Either I’d recognised the voice, or I’d been thinking all along that if Groomed had been able to catch me, he’d have had no trouble getting hold of Woolf.

Or Sarah, come to that.

I closed the door and propped a chair on two legs under the handle. It wouldn’t stop anyone, but it would give me a chance to get off three or four rounds before the door opened. I knelt down in front of Woolf, and immediately swore at a new pain in my knee. I shifted back and looked at the floor. Seven or eight oily-looking nuts and bolts lay at Woolf’s feet, and I leant down to brush them away.

But they weren’t nuts and bolts, and it wasn’t oil. I was kneeling on his teeth.

I undid the straps and tried lifting his head. Both eyes were closed, but I couldn’t tell whether that was because he was unconscious or because the tissue round his cheeks and eye sockets was horribly swollen. Bubbles of blood and saliva hung round his mouth and his breathing sounded terrible.

‘You’re going to be fine,’ I said. But I didn’t believe me, and I doubt whether he did. ‘Where’s Sarah?’

He didn’t answer, but I could see he was struggling to open his left eye. He tilted his head back and a low grunt burst some of the bubbles round his lips. I leaned forward and took hold of his hands.

‘Where’s Sarah?’ I repeated, with a thick, hairy fist of worry gripping at my larynx. He didn’t move for a while, and I began to think he’d passed out, but then his chest heaved and he opened his mouth as if he was yawning.

‘What do you say, Thomas?’ The voice was a thin rasp, and his breathing was getting worse by the second. ‘Are you…’ He stopped to suck in some more air.

I knew he shouldn’t keep talking. I knew I should tell him to keep quiet and save his strength, but I couldn’t do it. I wanted him to talk. To say anything. About how bad he felt, about who had done this, about Sarah, about racing atDoncaster. Anything to do with life.

‘Am I what?’ I said. ‘Are you a good man?’ I think he smiled.

I stayed like that for a while, watching him, trying to think what to do. If I moved him, he might die. If I didn’t move him, he would die. I even think that part of me actually wanted him to die, so that I could be free to do something. Take revenge. Run away. Get angry.

And then suddenly, almost before I knew it, I was letting go of his hands and picking up the Glock, moving sideways across the room in as low a crouch as I could manage.

Because someone was trying the door-handle.

The chair held firm for a push or two and then slid away from the handle as a foot crashed against it. The door swung wide and a man stood in its place, taller than I’d remembered, which is why I took a few tenths to realise that it was Groomed and that he was pointing a gun into the middle of the room. Woolf started to get up out of the chair, or perhaps he was just falling forward, and there was a long, loud crash which tailed off into a series of flat bangs as I fired six shots into Groomed’s head and body. He fell back into the corridor and I followed him, firing another three into his chest as he went down. I kicked the gun away from his hand and pointed the Glock at the middle of his head. Cartridge cases trickled across the floor of the corridor.

I turned back into the room. Woolf was six feet away from where I’d last seen him, lying on his back in a thickening black pool. I couldn’t understand how his body had travelled so far, until I looked down and saw Groomed’s weapon.