Nicholas returned an hour later and sprawled untidily on the opposite banquette. ‘We’d better talk,’ he said. ‘I’d better talk. You understand this thing we’re in?’

He leaned towards me and looked in my eyes. I could smell alcohol on his breath. I had the awful sensation of being disgusted by the sight of my own face.

‘It wasn’t an easy decision to make,’ he said.

He wasn’t being truthful: the decision was easy; what he was finding difficult were the consequences.

‘Vera and I spoke about this,’ he went on. ‘Something happening to her. She was going to write you a letter, but it would have been compromising. I’m supposed to tell you that there will be a gap.’

From the volume of his voice and his awkwardness with me, I got the feeling he thought I was all gap.

‘The way the Procedure works, there’s a hiatus – it’s called an entelechic or mnemonic hiatus. It’s scientific periphrasis. They’re just nervous about calling it amnesia.’ He closed his eyes and covered his face with his hands. It was a gesture of despair. I could hear his drunken breath whistling in his nostrils. ‘Just tell me: do you have any idea who I am? Do you remember anything at all?’

I looked at him for a moment, then I shut my eyes and visualised the mouthparts of the anatomical head. I forced my tongue into the gap between my parted teeth and breathed out. I could feel the muscles in my throat tighten. The sound originated somewhere in my abdomen. ‘Th-this,’ I said. The word faded away into silence like a hiss of steam.

‘Well, that’s a start,’ he said. I opened my eyes and he was looking at me with a new alertness.

Seconds passed. I manoeuvred my lips to make the tiniest possible aperture. After a tentative start, the sound emerged with surprising clarity: ‘World.’ Now I threw my head back and felt my face contort. My left foot rose on tiptoe from the strain. ‘Of.’ As I struggled to maintain the muscle tone in my jaw, my hands spontaneously formed fists. I spat all my rage and contempt into the next word: ‘Dew.’

The blood was draining from his face as he looked at me in horror, but I was determined to give him the full proof of life. I went on, my articulation decreasing in clarity with every syllable. ‘Isaworld. Of. Dew. Andyet. And yet.’ The tension finally left me. I flopped against the seat back. It was no longer hot in the carriage, but I had broken out in a sweat from the effort.

With every fibre of my new body, I understood the associations those words evoked for him. It was his favourite poem: Issa’s perfect haiku, compressing a glimpse of infinity into a handful of syllables, lamenting the intrusion of death and change into every life, awakening Nicholas’s sense of grief for his father, his mother, his sister. He looked as though he had been slapped. He fell back against the banquette and stared at me, open-mouthed, in shock.

What must he have been thinking? To acknowledge intellectually the possibility of the Procedure was one thing, but to be confronted by your double, your fetch. We’d both read enough to understand that, in myth at least, such a thing never ends well.

Suddenly, we were interrupted by a noise at the door of our coupé. Outside, someone was wrestling with the handle. Nicholas stiffened for an instant then grabbed the door and held it shut. ‘Zanyat!’ he shouted. ‘It’s occupied. Occupé! Besetzt!’ The noise stopped. There were footsteps. Nicholas slid open the door a crack. I could see a puzzled Kazakh retreating down the corridor apologetically.

‘My nerves are shot,’ Nicholas said. And then: ‘You must be starving.’

Vera had packed some food – hardboiled eggs, a wheel of Uzbek bread – and at the next stop, Nicholas bought two polystyrene pots of instant noodles on the platform and rehydrated them with water from the guard’s samovar. Textured soya chunks floated in the broth. He fed me with a plastic fork as the locomotive tugged us across the steppe with a distinctive uneven rhythm. In the dying light, cows or sheep were just visible on the vast pastures outside the window as tiny, ant-shaped dots.

‘It’s got to be stopped,’ he said. ‘Vera and I agreed on that. It’s an abomination. Fedorov wanted to help the whole of humanity. But this is just like every other utopian scheme. Something that’s supposed to be a gift for humanity in general diminishes the worth of individual humans to zero. You can see what happens next: life itself will become another good that the rich get more of. Vera said they’re already talking about having two classes of proxy complex: zachots and pyaterki. Only the pyaterki will have full consciousness. It’s unspeakable. They’ve been stepping up the numbers. The survival rate is abysmal. But each resuscitation makes subsequent ones easier.’

Nicholas was right to be disgusted: there was nothing egalitarian about this version of the Common Task. It was of a piece with the primal unfairness that has seen favoured consciousnesses hogging power, food and opportunities for reproduction since our ancestors crept out of the ocean. I share his moral outrage.

The gap he was talking about had begun for me in the hotel room in Moscow. That was the moment our experience bifurcated. Our consciousness had split in two like a cell undergoing mitosis. From a storm of almost ineffable images, I had emerged into the hospital bed in Baikonur.

For Nicholas there was no comparable break. He said there had been direct threats to him in Moscow. Two men had tried to abduct him from outside his hotel in broad daylight. He had come to the realisation that Vera was telling the truth and had concluded that they had to act. I was his idea: a double who would be tangible evidence of the Common Task.

Vera, he said, had been initially reluctant. She worried that it would compound the ethical lapse of getting involved with the Procedure in the first place. But what else would provide definitive proof? Vera had said it herself: it couldn’t be grasped intellectually. Words were not enough. Like the Apostle Thomas, the human mind needs the touch of flesh to assuage its doubts.

Nicholas had supplied her with his journals, his writings, all the supplementary data she needed. She’d generated a code. It was handcarried in a diplomatic bag to Baikonur and slipped into the most recent batch of resuscitations. They’d had to rush. At the time of my release from the facility I was still some way away from full rehabilitation. Judged purely as a medical matter, my discharge was clearly premature, but Vera sanctioned it while she still had the authority to do so. She needed to do it before her subversion came to light.

We lay parallel in our narrow berths. The carriage rocked in the darkness. ‘We’re going to have to move quickly when we get back,’ he said. ‘They’ll be after us. As soon as you’re ready, we’ll go to the authorities. If the police won’t act, we’ll go public. Vera’s drawn up a list of the great and the good: scientists, human rights lawyers. The world’s got to know what’s being done. Can you imagine what Johnson would have made of this, an unholy combination of slavery and forgery?’

There was excitement in his voice, a bracing sense of the importance of his task. I almost didn’t recognise him. Nicholas had never done an impetuous thing in his life. Now, he suddenly had a taste of life as a combatant in an honourable cause. There was an elation about him: the same energising change that comes over Hamlet when he returns to Denmark from England towards the end of the play, transformed from worrier to warrior.

It had grown colder in the compartment as we made our way across the steppe. Nicholas finally fell silent. I assumed he’d gone to sleep. He must have been exhausted. A few moments later, I was aware of someone standing on the end of my bunk and reaching up into the cubby-hole above the compartment. I closed my eyes and wondered what he was doing. Something dropped on me. He had covered me up with a blanket.