Sprage went on, ‘Gosk Balem was an ECS soldier who was captured by Hoop and his crew. They brought him here to be cored like the rest of their captives, but as he was ECS, and so obviously horrified by what they were doing here, Hoop decided to keep him alive in order to extend his suffering. They forced a slave collar on him, then put him to work at the furnace, burning the physical remains of coring. He had no idea then that those remains were still living and, even had he known, would he have chosen not to burn them? Would any of you?’

Silence met this question, so Sprage continued: ‘The Hoopers that were cored were too recently infected with the virus to have survived long in that ganglionic form. Those that weren’t eaten by leeches would have died or slowly transformed into leeches themselves. He never burned anything that still had a chance at life. He worked for Hoop because he made the choice of survival.’

‘Yeah,’ said Boris. ‘But he didn’t have the slave collar on all the time.’

‘Survival again,’ said Sprage. ‘Hoop removed his collar so as to further extend his torment. He could try to flee into the wilds, but it was unlikely he would have succeeded. Hoop really wanted him to try. Instead, he stayed and he continued feeding remains into the furnaces. And do you know why? Because while he was there, he might find the chance to act against Hoop.’

‘How do you know all this, Sprage?’ asked Ron.

Sprage took a short penknife from his pocket and scraped round in the bowl of his pipe. After knocking out the pipe’s dottle on the palm of his hand, he immediately began to refill it.

‘I know because I saw him doing something then that I only came to understand a few years after we caught him and threw him in the sea. The furnaces were powered by an old fusion reactor Hoop had removed from one of his landing craft. I still had my collar on then, while the virus established itself in me. I was three weeks, a month perhaps, from being cored. It was at that time I saw him carry a piece of reactor shielding and drop it in the moat.’

Abruptly Keech was on his feet, having been squatting by the flames. ‘He what?’ said the monitor.

‘The war was ending and the Prador retreating,’ said Sprage, ignoring Keech. ‘There’d been little chance of rescue during the war, but as it ended there was hope.’ He turned to address Keech. ‘You came here then. It was you who broke the program controlling the slave collars, and helped free those who remained. But how did you know where to come?’

Keech stared at Ambel, who was looking increasingly puzzled.