‘I can take a taxi home. I wanted to get a few things from the deli. I don’t feel like cooking tonight.’

The old woman took an already-segmented orange from a plastic tub and put a piece in her mouth, leaving me in no doubt about her identity. Oranges were the recognition signal Maxine and I had decided on.

‘Glad to know I’m worth so much effort,’ Zac said.

‘I’ll pick up some steaks.’

‘Don’t bother. I need to go to London tonight.’ The line went dead.

Good, I thought. Now I can eat my chocolate pralines without your fake-concerned comments about my putting on too much baby weight, and your pretend worries that I’ll be distressed when my body doesn’t snap back after she is born.

The old woman had finished chewing her orange segment. ‘Nice afternoon.’ She didn’t change her voice.

I let my eyes slide over her. The make-up and clothes and posture were so good she could be my grandmother’s best friend.

‘Yes. Isn’t it.’ I switched the phone off and slid the handset beneath me so that I was sitting on it. If he’d installed a bug app, then this would thwart him – a counter-measure I felt amused by.

‘Heidi Keyes,’ Maxine said. ‘Clever. What kind of hidden key?’

‘Something fell out of his pocket while we were in London a few days ago. We were in our hotel room. I think it was one of those micro SD cards. SD is Secure Digital, isn’t it?’

‘Yes.’

‘I only glimpsed it. He was drunk and furious. Not in control. He muttered about a key – I’m not sure what he meant – it was an upsetting time.’

‘Upsetting how?’

My face went hot when I thought of how he behaved in our room after my return from the British Library. ‘He—’ I broke off, and gave her a different truth. ‘He was anxious that the card might have been corrupted, because it got wet.’

‘Very slight possibility, but water damage would be unlikely,’ she said. ‘Those things are pretty protected and robust.’

‘What do you think he’s doing, Maxine?’

‘We need to see. But it’s useful to know about that card. You’ve done well. Any chance he still has it?’

‘I don’t think so. He was supposed to meet someone for dinner that night, to pass on some research. I think it was probably on that card.’ I felt a wave of the pregnancy nausea I’d thought was finally in the past, wondering again if the encrypted material was film footage he’d taken of me, remembering also how sick I’d been in London.

‘Did he say who this person was?’

‘A medical colleague. He said the man cancelled. I’m not sure he did, though. I fell asleep early that night – I wasn’t feeling well – and Zac was out until very late.’