‘Why?’ He shook his head. I could guess why he didn’t want me here. ‘No, I’ll stay.’

‘When it gets too much, go into the bedroom.’ He stood rubbing his limbs. He hoisted Grest up and slapped his face a few times, until Grest started to whimper and turn away from the light blows. ‘I’m glad you’re awake,’ said Tibbot. ‘It makes it easier.’ He stabbed Grest hard in the ribs with his truncheon. The Sec cried out in pain and struggled. ‘Probably cracked one,’ Tibbot said. ‘I’ll do them all soon. You’ve seen it from the other side. You know what it looks like.’

‘I know who you are,’ Grest mumbled.

Tibbot shoved him back on to the bare floorboards, took his truncheon and placed it across Grest’s throat. He put his hands on each end and leaned on it, choking him. Grest tried to squirm away, but he was pinned too tightly and his eyelids fell. ‘You think that worries me?’ He lifted the truncheon. ‘What did you do to Lorelei Addington?’ Grest drew in air with a hollow, rattling sound. ‘What was it? Did you hold her under the water? Was that what you did?’

The Sec didn’t answer. The loathing that I felt for him – he seemed less than human to me now – worked against the aversion I felt for the violence.

Tibbot stood up. ‘All right. You know, I haven’t been trained in this, like you have. Me, I arrest people who steal from their neighbours, or sell a few black-market tins of peas from their cars. So I don’t really know what I’m doing with you.’ He took his truncheon and brought it down on Grest’s chest. ‘Your heart’s right where I hit you. Can that cause a heart seizure? I don’t know. But you’re young and fit, so you can probably take it.’ He rubbed his brow. Grest’s lips seemed to be searching for something to say. ‘There’s a science to it, isn’t there? Things that the Nazis developed and the Russians borrowed. And they passed it on to you. I don’t know about that. I’m as likely to kill you as get the truth out of you.’ I couldn’t tell if Tibbot’s words were empty threats or if I had never really known him and what he was capable of. I hated the man on the floor, but the prospect of being there when he was killed made me stop and take a step back.