And then: “Hey, boy, don’t bother me.” After that she was silent and avoided engaging directly with her reflection.

Now Coleridge saw Carlisle’s hand reach out beyond the front of his camera. He was holding something – a small white pouch which he took by a corner and shook. There was a tiny rattling sound in the deathly silence of the dark tunnel, and Coleridge realized with surprise what the pouch was: he had shaken one like it himself only a few weeks before during a hill walk in Snowdonia. It was a walker’s instant heat pack, an envelope full of chemicals and iron filings designed to produce a great heat in moments of need. He watched, amazed, as Carlisle crunched the pouch in his fist to form a blunt point, and began to trace letters on the glass. Clearly the heat was intended to warm the condensation on the other side.

Carlisle wrote slowly, partly no doubt in order to give the heat time to conduct through the glass, but also, it seemed to Coleridge, because Carlisle was enjoying himself. His forefinger was gently stroking the glass, following the line traced by the heat pack, almost as if, by touching the two-way mirror, Carlisle felt he was in some way touching Dervla. Coleridge strained to see what Carlisle was writing. The letters were inscribed backwards, of course, but they were not difficult to follow.

On the other side of the glass Dervla was watching too, her eyes darting downwards as the message appeared.

“Don’t worry. People still care about you,” emerged though the condensation.

Dervla’s expression did not change. She kept her eyes fixed on the letters.

Behind the glass in the dark corridor, unaware that he was being observed by a police inspector, Carlisle stretched out his arm and wrote a few more words.

“Nobody out here thinks you did it.”

Three separate pairs of eyes watched as the words were slowly spelled out: “But you’re number one now. The people love you… and so do I.”

Coleridge was an accomplished watcher of faces, and he knew Dervla’s well from many hours of study. As he looked he saw clearly the distaste that flickered across her face.

“La de da,” she said, with a shrug of indifference, and began to brush her teeth.

Coleridge could sense Carlisle’s tension as the cameraman fumbled to lock focus on his machine and get sight of Dervla through his own little camcorder. Clearly Carlisle coveted every image of his secret love, and once more he pushed his little lens as close to the glass as he dared without tapping it. First he stole himself a close-up of the dark tuft of hair in Dervla’s armpit, revealed to him because her arm was raised to brush her teeth. Then he panned across a little in order to capture the faint jiggling of her breasts beneath the towel caused by the movement of her arm. Finally, with the practised timing brought by experience, he swung his sights upwards just in time to capture the unwitting girl spitting the toothpaste from between her lips. Coleridge could hear the tiny motor of the camcorder hum as Carlisle zoomed into extreme close-up on Dervla’s wet, white, foaming mouth.

When she had finished, Dervla went out of the bathroom and back to the girls’ bedroom. The house was silent once more. All of the inmates were in the two bedrooms on the opposite side of the house from Soapy corridor. Coleridge pressed the button on the little communicator that the Peeping Tom sound department had given him, which alerted Geraldine in the control room to the fact that he had seen enough.

A moment or two later Carlisle left his camera, having been recalled by Geraldine under some professional pretext, as she had promised to do.

Coleridge followed Carlisle out as he left the corridor. Once outside, blinking in the striplight of the communication tunnel that linked the house with the control complex, Coleridge laid his hand on Carlisle’s collar in time-honoured fashion, and asked him to accompany him to the station.

DAY FORTY-FIVE. 12.00 noon

“Oh my God, I think I’m going to be sick. I really do think I’m going to be sick.”

Coleridge was showing Dervla some of the contents of the camcorder that he had taken from Larry Carlisle. Stacked up beside the VCR were seventeen similar mini-cassettes, retrieved by the police from Carlisle’s home.

“You seem to have become something of an addiction for this man,” Coleridge said. “Viewing his tape collection, it looks like he simply could not get enough of you.”

“Please don’t. It’s horrible, horrible.”

There was so much of it. Hours and hours of tape. Close-ups of Dervla’s lips when she talked, when she ate, her eyes, her ears, her fingers, but most of all, of course, her body. Carlisle had recorded virtually every single moment that she had spent in the bathroom from day three onwards, becoming ever more practised at gaining close-ups of any intimate area that had been carelessly revealed to him.

Often in the shower the weight of the water had pulled at Dervla’s sodden knickers, revealing the top of her pubic hair and, when she turned round, an inch or so of the cleft of her bottom. Carlisle had clearly lived for these moments, and he zoomed in to extreme close-up whenever the opportunity arose.

“I can’t believe I’ve been so stupid,” Dervla said, her voice choking with disgust and embarrassment. “Of course, I should have guessed why he was being so encouraging towards me, but I had no idea… I…”

Dervla, normally so strong, so self-assured, contemplated the creepily silent dislocated images of her own body on the screen, a body rarely viewed whole but broken up into intrusive, intimate close-ups, and she wept. The tears ran down her face as the soapy water on the screen ran down her stomach and her thighs.

“Did you get messages in the mirror every day?”

“Not every day, but most days.”

“What did they say?”

“Oh, nothing very startling. ‘How are you?’ That kind of thing. ‘You’re doing great’.”

“So he talked about the game.”

“Well, not in any great detail. He was writing backwards in condensed steam, after all.”

“Did he ever mention Kelly?”

“No.”

It was a fool’s lie.

“Actually, yes, I think he did mention her,” Dervla said quickly.

“Yes or no, Miss Nolan?”

“I just said yes, didn’t I? Sometimes… a little… he mentioned them all.”

Half a lie. Was that any better? Or worse?

“I don’t know why he sent me messages,” she added. “I never asked him to.”

“He’s in love with you, Miss Nolan.”

“Please don’t say that.”

“He loves you, Dervla, and that is something that you are going to have to deal with, because I doubt that what he has done is going to get him any kind of prison sentence. When you come out of the house he’ll be waiting for you.”

“You really think so?”

“That’s my experience of obsessives. They can’t just turn it off. You see, he thinks you love him back. After all, you’ve been flirting with him for weeks.”

“I haven’t…” But even as she said it Dervla knew that denial was pointless. “I… just sort of fell into it,” she continued. “It was a laugh, a game. It’s so boring in that house. The same dull stupid people that you can’t even really get to like because you’re in competition with them. You’ve no idea… And then there was this jokey thing going on, just for me. I had a secret friend on the outside who wished me luck and told me I was doing all right. You can’t imagine how weird and insecure it is in that house, how vulnerable you feel. It was nice to have a secret friend.”

Dervla looked at the screen on which Larry Carlisle’s tape was still playing. She was in the shower again, her hand inside the cups of her sodden bra, soaping her breasts, the shape of her nipples clearly visible. “Can we turn that off, please?”