‘Nope, I haven’t been since, ooh, must be at least five years. Someone said they were me, you say?’

‘Not exactly. He had your badge on.’

‘Hmm.’ He thought for a moment, drumming his hands against the desk. I noticed they were very nice, square and capable, the nails filed down. ‘You know what, I think the hospital could well have signed me up. The drug companies fund it so it’s no skin off their nose. There’d have been a badge for me, maybe.’

‘And they don’t check ID or anything, when you pick them up?’

‘Lord no, why would anyone want to blag their way into that snooze-fest? Though maybe someone did, by the sounds of it.’ He sat back, pleased at having solved the mystery. ‘So what did he do, this identity thief? Give you some bad medical advice?’

‘Oh no, nothing like that. He just – mentioned the birth centre here was very good, that’s all. I wanted to look him up for some advice.’ I hadn’t been pregnant then, obviously, but I hoped it would go unquestioned.

‘You’re in medicine too? Or a rep?’

‘No, I’m . . . I was at something else in the same hotel. We just got chatting.’ I had to stop this conversation, before I got found out, before I laid a trail that Nick could follow all the way back. But I couldn’t leave. I had to keep picking at the mystery, like a rat in a maze, scrabbling for its dopamine fix. ‘Dr Holt – this might be a weird question too, but is there anyone in your department called Sean Sullivan?’ Perhaps the story had been true. Dr Holt was a colleague of yours, and it really was a simple mix-up. I’m sorry I doubted you.

He was frowning again. ‘Sean? None of the doctors, that I know of. And I don’t think nursing staff. Maybe in management. I can find out, if you like? Wait a sec.’ And before I could stop him he’d bounded to his feet and was opening the door to the corridor. ‘Jim? Do we have a Sean Sullivan in the admin team, do you know?’

I stood. The door was half open, but I could see through the gap that he was talking to an older doctor, whose white coat was rumpled and eyes red-rimmed. Not someone I’d want treating me, I decided in a glance. When he spoke he coughed first, a smoker’s rasp. And then he said, ‘You mean Patrick Sullivan? The finance clerk?’

Dr Holt looked at me. You’d told me Sean. You’d also told me you were a doctor and that you lived in Kent. I managed to say, ‘I don’t know. Dark hair, glasses, very blue eyes?’ Even the memory of them could send me sagging to the floor, all strength gone.