I sit down in the grey plastic chair in the featureless room with McDunn and a man from the Welsh squad; a big blond brindle guy in a tight grey suit; he has a rugby player's neck and steely eyes and huge hands that are clasped on the table, lying there like a mace of flesh and bone.

McDunn's eyes narrow. He makes that sucking noise through his teeth. "What you been doing to your eyes, Cameron?"

I swallow, take a long sigh and look at him. "Crying," I tell him. He looks surprised. The Welsh boyo looks to one side.

"Crying, Cameron?" McDunn says, his dark, heavy-looking face creasing into a frown. I take a deep breath, trying to control things. "You said Andy was dead. Andy Gould. He was my best friend. He was my best friend and I didn't… fucking… kill him, all right?"

McDunn looks at me, as though slightly puzzled. The Welsh lad's got this steady gaze on me like he wants to use my head as a rugby ball.

Another deep breath. "So I've been grieving for him." And another. "Is that all right?"

McDunn nods slowly, slightly, a distant look in his eyes like he's not really nodding at what I've just told him; hasn't been listening to a word I've said, in fact.

The Welsh guy clears his throat and picks up his briefcase. He takes out some papers and another tape recorder. He passes an A4 sheet over to me. "Just read out the words on this sheet of paper, all right, Colley?"

I read the words through first; looks like it's the statement our man phoned in after Sir Rufus was flame-grilled; Welsh Nationalist extremists apparently claiming responsibility.

"Any particular voice?" I ask. "Michael Caine, John Wayne, Tom Jones?"

"Let's try your own voice first, eh?" steely-eyes says. "Then we'll try you with a Welsh accent." He smiles, the way I imagine a prop forward smiles just before he bites your ear off.

"Cigarette?"

Ta."

Afternoon session. McDunn again; McDunn seems to be settling out as the Colley specialist. He lights a cigarette for me, holding it in his mouth. My hands aren't shaking so bad right now so maybe this isn't strictly necessary but I don't care. He hands the fag to me. I take it and it tastes good. I cough a bit but it still tastes good. McDunn looks on sympathetically. I actually find that I appreciate this. I know how they're supposed to work, I know all about the importance attached to establishing a rapport and initiating trust and building confidence and all that shit (and I'm almost flattered they haven't done the old good-cop bad-cop routine, though maybe they just don't do that at all any more because everybody knows about it from the TV), but I really do feel something for McDunn: he's like my lifeline back to reality, my ray of sanity in the nightmare. I'm trying not to get too dependent on him but it's hard not to.

"So?" I say, sitting back in the grey plastic seat. I'm wearing a blue prison-issue shirt — open-neck, of course — and the jeans I was wearing when they arrested me. They don't hug so well without the belt; bum's a little saggy, to tell the truth, but fashion isn't my top priority these days.

"Well," McDunn says, looking at his notebook, "we've found people who think they remember seeing you in the Broughton Arms Hotel on the night of Sunday the twenty-fifth of October, when Sir Rufus was murdered."

"Good, good," I nod.

"And the times for you getting down to London for the attack on Oliver, if you include the times you — or whoever — were seen in the toilets at Tottenham Court Road, are looking very tight; there was a delay on all the flights from Edinburgh into Heathrow that day… makes it impossible, really."

"Great," I say, rocking back and forward in my seat. "Brilliant."

"Unless," he says, "you had a double in Edinburgh or a lot of people are lying, it means you'd have to have an accomplice in London; somebody you'd hired to… ah, make the collection." McDunn looks at me levelly. I still can't read him; I'm not able to tell whether he thinks this is likely or not, whether he thinks this is evidence I'm not his man or he still thinks I am but I had help.

"Well, look," I say, "put me on an identity parade —»

"Now, now, Cameron," McDunn says tolerantly. This is something I've suggested before, something I keep on suggesting because it's all I can think of. Will the limbless Mr Azul think I'm the guy he saw at the front door? What about rent boys from the toilets at TCR? The cops think I'm the right build and they suspect gorilla man wears a wig and false moustache sometimes and maybe false teeth too. They've taken some very carefully set-up photographs with a big fucking camera and I suspect — from an aside or two they probably didn't expect me to understand — that these snaps will be the basis for some computer manipulation to see how well I fit the bill. Anyway, the upshot is McDunn doesn't think it's time for a parade yet. He looks wise and fatherly and says, "I don't think we want to be bothered with that, do you?"

"Come on, McDunn, give me a shot; I'll try anything. I want out of here."

McDunn taps the fag packet round and round on the table a couple of times. "Well, that's up to you, isn't it, Cameron?"

"Eh? What do you mean?"

Oh, he's got me now; I'm interested, I'm leaning forward, elbows on table, face forward. Hooked, in other words. Whatever he's going to try and sell me, I'm buying.

"Cameron," he says, like he's just come to some big decision, and sucks air through his teeth, "you know I don't think it's you."

"Oh, great!" I say, and laugh, sitting back and looking round the room at the bare paint walls and the constable sitting by the door. "Then what the fuck am I —?"

"It's not just me, Cameron," he says tolerantly. "You know that."

"Then what —?"

"Let me be frank with you, Cameron."

"Oh, be as frank as you like, Detective Inspector."

"I don't think it's you, Cameron, but I think you know who it is."

I put my hand to my brow, looking down and shaking my head, then sigh theatrically and look at him, letting my shoulders slump. "Well, I don't know who it is, McDunn; if I did I'd tell you."

"No, you can't tell me yet," McDunn says quietly and reasonably. "You know who it is, but… you don't know that you know." I stare at him. McDunn's going metaphysical on me. Oh, shit. "You're saying it's somebody I know."

McDunn splays one hand, smiling smally. He chooses to tap his fag packet round and round on the tabletop again rather than speak to me, so I say, "Well, I'm not sure about that, but it's certainly somebody who knows me; I mean, I think that card with my writing on it proves that. Or, it's something to do with those guys in the —»

"— Lake District," McDunn sighs. "Yes…" The DI thinks my theory it's the security forces trying to fit me up is pure paranoia. "No." He shakes his head. "I think it is somebody you know, Cameron; I think it's somebody you know well. You see, I think you know them as well… well, nearly as well… as they know you. I think you can tell me who it is, I really do. You only have to think about it." He smiles. "That's all you have to do for me. Just think."

"Just think," I repeat. I nod at the DI. He nods back. "Just think," I say again. McDunn nods.

Summer in Strathspeld: the first really hot day that year, air warm and thick with the coconut smell of gorse — swathed richly yellow on the hills — and the sweet sharpness of pine resin, lying dropleted on the rough trunks in thick translucent bubbles. Insects buzzed and butterflies filled the glades with silent flashes of colour; in the fields the corncrake stooped and zoomed, its strange, percussive call stuttering through the scent-laden air.

Andy and I went down by the river and the loch, clambering up the rocks upstream then back down, watching fish jump lazily out on the calm loch, or strike at the insects speckling those flat waters, jaws snapping underneath; dispatching, swallowing, leaving ripples. We climbed some trees looking for nests but didn't find any.