We had a lot of religious nutcases in the DHU. One of the most likeable was the mixed-race man who called himself Caiaphas. He would pad around the unit most afternoons with a tattered stack of Watchtowers, the Jehovah’s Witness magazine, which he would hand out and then come by to collect about fifteen minutes later. It says something about the basic decency of the loonies in there that everyone colluded with his harmless nuttiness, accepting the magazines and then returning them without complaint almost immediately.

One afternoon, he came by, selected a magazine from the big wad in his hand, changed his mind, selected another and dropped it at the foot of my bed. ‘Haven’t seen you around much, brother.’

I explained, through my involuntarily clenching jaw, that I’d been in the seclusion cells and that White had put me on a punitive dose of neuroleptic drugs.

‘Someone’s been looking for you,’ he said. ‘He knows your name.’

Dimly, through the hum of interior noise, I could tell that this information ought to be important to me.

‘Staff or client?’ I asked him.

‘Client.’

‘Does he know who I am?’

‘Not from me, brother.’

‘What’s his name?’

‘Doesn’t say.’

It took me so long to formulate my next response that by the time I had, Caiaphas had gone.

*

In a world as empty of solace as the DHU, the most humanising thing we had was the caress of water. I took showers as often as I could, at least once a day. We couldn’t control the temperature, or even the pressure; the shower ran in twenty-second bursts each time you depressed its button. But for each of those twenty seconds, the water on my scalp was an angel’s fingers, and I could stand still, and the heat on my spine relieved its constant aching.

The shower rooms themselves were unsupervised. An attendant sat outside, checking us in and out: we had to book our slots in advance.

Two or three evenings later – it’s hard to be precise because of the time-bending quality of the drugs I was on – I flapped round to the washrooms in my dressing gown and flipflops. There were six shower cubicles, three on each side at one end of the room, and a changing area with plastic chairs and hooks to hang clothes and towels; but they were rarely, if ever, fully occupied.

Someone came and went in the stall next to mine. Through the steam I was aware of someone in the changing room undressing and folding his clothing scrupulously into a tidy pile.

The hiss of water drowned out the buzz of the chemicals in my head. I closed my eyes and for a brief and blissful moment the carcass was at rest.

In the next instant, I was struck a huge blow across my back and shoulders and fell to my hands and knees. Something closed round my neck. I was able to slip my right hand through it as it tightened and leather bit into my wrist. Yielding to the upward pressure, I allowed my assailant to pull me back onto my feet as he tried to choke me, then I moved with him, adding my bulk to his, and slammed him into the thin partition that divided mine from the neighbouring cubicle; it surrendered and split. We fell together. Someone was cut from the splinters of laminated plywood. Still throttling me from behind, my attacker brought his knees repeatedly into my ribs, encouraging me to drop my right hand to parry them and leave my throat unguarded. As I struggled to shake him off my back, I sensed myself weakening.

‘Who are you?’ I croaked.

He gave no indication that he had heard. He was breathing more heavily and his kicks had slowed a little, but he continued to tighten the belt. My vision grew strangely sharp: I could see beads of moisture on the wall tiles, mildew on the grouting. I glanced down to my left. For an instant, I mistook his leg for mine. There, on the upper face of his left thigh, was a roundel identical to the one that marked me: the same size, the same pattern, the same location; the colours fresher and more sharply delineated.

The surge of adrenalin that followed brought a measure of lucidity to my drug-clouded brain. I remembered the sessions at the clinic in Baikonur.

I gathered the little breath I had left in a final effort to communicate. ‘My name is John Smith,’ I said through gasps. ‘It’s important to me that we do this exercise properly. Do you understand?’

The belt went abruptly slack. I manoeuvred myself around to face him.

We were lying in a heap on the floor of the shower cubicle. Blood and water puddled on the tiles around us.

He wasn’t an inmate I’d ever seen before. He was about the same age as me, slightly shorter and less heavy-set. He might have been chosen for his absence of distinguishing features. His fair hair was cropped or thinning. His face was empty of expression and his eyes held a terrifying blankness.

‘Please indicate that you’ve understood,’ I said.

The nod he gave seemed almost involuntary.

‘Good job,’ I said. ‘Now, I’m going to show you an array of pictures and I’m going to ask you to pick one. Do you understand?’

There was no nod this time. He narrowed his eyes, as though I were coming into focus.

‘It’s important to me that we do this exercise properly,’ I said.

His face had the suddenly alert expression of someone who has heard his name called from a distance. In that millisecond of hesitation, I hit him as hard as I could. His head slumped against the partition and I ran.

*

My injuries weren’t severe enough to merit a spell in the medical ward, but the cuts from the splintered wood required stitches, and the assault itself triggered a formal inquiry by Dr White and two approved mental health professionals.

I explained to them, as lucidly as I could, that my assailant, whose name they claimed was either Thomas Roberts or Robert Thomas, had launched his attack on me for no reason that I could fathom. I didn’t want to alienate the possibly sympathetic supervisors with what seemed to me undeniable: that the man was a zachot, a programmed assassin, who had been inserted into the Dennis Hill Unit in order to kill me, but I did point out the bizarre coincidence of our identical tattoos and I asked that Dr Webster be called to speak on my behalf.

It seemed like a reasonable request, even to Mumford and Kumar, the mental health professionals who made up the quorum with White on the panel and who had, at first glance, given every indication of being precisely the kind of obedient, risk-averse mediocrities one would need to whitewash an assassination attempt.

Mumford, to his credit, even suggested they adjourn the inquiry until Dr Webster could come in. However, as the senior member of staff, White was able to overrule them. He harrumphed at the pointlessness of the idea. Besides, he said, Webster was on indefinite personal leave. In his subsequent questions to me, he played down the significance of the tattoos and played up what he called the sexual component of the incident. The other client, he claimed, was alleging that I’d tried to assault him.

If I hadn’t been so heavily medicated, I would have laughed in his face. I asked him how the bruising to my back conformed to that theory; and to explain why, for that matter, I hadn’t sodomised the man when I had him at my mercy.

‘Didn’t you?’ he asked. ‘I don’t know. Why didn’t you?’ The crude effort to depict me as a sexual predator was clearly intended to provoke me into another outburst. Mumford and Kumar exchanged uncomfortable glances. To them, White’s harshness was beginning to look both unprofessional and mean-spirited. To me, it was further confirmation of the scope and resourcefulness of the Common Task. I had no doubt that White had been suborned. I wanted to ask him if he had any pride. Didn’t he remember the scandal of Soviet psychiatry? How did he justify putting his profession at the service of a criminal cabal? But I held my tongue for fear of antagonising him.