The open-plan area was still hushed – Clovis and Rayah turning bleak faces and murmuring insipid hellos. There was no sign of Pamela; the door to Morahan’s office remained shut. Patrick unlocked the Legal office door.

‘I’ve brought the files in,’ he said, ‘we’re going to show them to someone.’

‘What?’ murmured Sara.

He extracted a folder from his case, and headed for the door. ‘Come with me.’ He turned left and knocked on the adjoining door; it was unlocked and he entered without waiting for an answer.

A surprised face whipped round, lowering broad, grey-rimmed spectacles. ‘Oh, the invasion of the Legals,’ said Sylvia Labone without enthusiasm.

‘Have you a moment, Sylvia?’

‘My God, what a question,’ she rasped.

‘I’ve something to show you. But first I want to know something.’ She examined him with an almost imperceptible show of interest. ‘Why didn’t you say? All these weeks and months you and I have been here, why didn’t you say?’

‘Don’t give me riddles, Patrick.’

‘That we’d met, of course. It came back to me in the night.’

‘You must have been dreaming.’

‘No. Not at all. Thames House. 2005. J had me in for a grilling. He went off to find a completely unnecessary cup of tea and you popped your head around the corner. I know, it’s thirteen years ago, but it was you. I was sitting alone and you said something like, “Can I help?” I looked up at this long-skirted ex-hippy – well, not quite – her face lined with the experience of life, and I think I said something like, “I’m fine, thanks, just waiting for him, et cetera.” You stared hard at me, said something and disappeared.’

‘Did I really?’ she mused, softening in a way Sara hadn’t seen before. ‘Did I really?’

‘Yes, Sylvia, you did,’ said Patrick. ‘I’ve only just clocked. J wanted you to give me the once over, didn’t he? The cup of tea was a feint.’

‘J,’ she said.

‘What did you tell him?’

‘I said I thought you were suitable.’

‘Suitable for what?’

‘Goodness, he’d never tell me that. I was just the archivist. When we had proper archives.’

‘Keeper of the secrets.’

‘So sad.’ She looked at her computer mournfully. ‘All kept in these machines now with their codes which any bright boy who can add two and two can enter. A real secret can only be held in the palm of a hand.’

Patrick dropped two slim folders on her desk. ‘Put these in your hand.’ Patrick sensed Sara’s agitation. She was frowning, her eyes begging silent questions. As Sylvia repositioned her spectacles, extracted the Blackburn files and buried her face in them, he put a forefinger to his mouth and signalled a quiescent ‘shush’.

‘Hmmm. Unredacted. The real thing.’ Sylvia spoke with little more than a murmur. ‘How did you get these?’