The train arrived and we boarded it. Tibbot was silent for a minute. Then he cleared his throat. ‘Look, Jane, I’m sure I don’t need to tell you, but we’re crossing a line here. I can’t tell them I’m a copper so we won’t have that protection. If NatSec or whoever found out, we would be –’

‘I know what we would be.’ He didn’t need to warn me. Maybe as a policeman he didn’t experience the visceral fear that the rest of us had to live with. But it was as much as I could do not to catch the first train back to London and wait quietly at home for whatever was going to happen to me and Nick. ‘I was wondering,’ I said, changing the subject. ‘Back in Lorelei’s house, when we were looking at the posters, you started to tell me something but you stopped yourself. It was something you had seen in them.’

‘Did I? Oh, yes, something did occur to me. Those dates on the posters – they meant something but not just the code in the book. Something else.’ I waited again for him to explain. ‘It’s that they were all years ago. The last one was in ’48. No more in the last four years.’

‘So?’

‘Oh, twenty years ago it must be. I was sent to a house up in Golders Green. I was living north of the river then. Actress by the name of – I won’t forget it – Lillian Hall-Davis. She was a big star for a while. Silent era – before your time. Then the talkies came and the parts dried up. Well, poor girl did for herself. Do you think –’

‘Lorelei would never do something like that.’

‘How can you be sure?’

‘Because she liked herself too much.’

It was fully dark when we alighted at a tiny station formed of nothing but a platform and a brick hut for the guard. The village it served was a vision of the rural England that used to be, and in my mind’s eye I could see old maids cycling to church, waving to mothers with prams, while the menfolk played cricket on the village green. There were pockets of that left, with the new way of life taking its time to creep out from the towns and cities, but there was talk now of collectivizing the last remaining private farms to make them fairer and more efficient – no longer would the farmer have a fat belly while the factory worker starved, they said.