Were the files themselves genuine? As a judge he was accustomed to recent police files, but his own experience of intelligence files on suspected terrorists went back to his brief time as Attorney General, mainly in the wake of 9/11, when the net was being cast far and wide. He tried to remember what these looked like; then realised it would be remarkable if the means of recording information in the digital age had not moved on. Did these print-outs have the ring of truth? Of authenticity? He stared at them again, working his way slowly through them, seeking out flaws or artificialities. If they were there, he could not see them.

If he could trust Sayyid it meant he must find an unusual kind of investigator. The memory of the Watergate ‘Deep Throat’, the prime cause of President Richard Nixon’s downfall in 1974, flashed before him. ‘Deep Throat’ had passed his secrets to journalist investigators – the celebrity duo of Woodward and Bernstein. He could hardly imagine himself entrusting anything to the modern breed of British journalist. To maintain control, he must recruit an investigator to work within his team. Sayyid had already said he could not trust any part of the security or police services but indicated he might offer further pointers.

It was late. He could not do this alone. He needed to find someone he could trust with the know-how to track down and win the confidence of the men in this file – men who might be both frightened and frightening.

Over breakfast, Francis and Iona sat opposite each other in their usual seats, he with The Times, she with the Guardian. She lowered her paper and folded it with a crack; he followed suit.

‘So…’ she began in her customary way.

He told her a great deal; the first approach, the methodology – he needed to explain the late-night strolls – and the nature of the printed-out files Sayyid had given him.

The telling prompted him to reflect on the rigmarole of Sayyid’s procedures. Surely there were simpler ways of doing this. It suddenly crossed his mind that Sayyid could be in some way playing him; deliberately conjuring him through a twisting chain of hoops. But why? To impress him? To whet his appetite? Even to compromise him? The idea that someone was setting a trap was monstrous; if he began to think that way, he was lost. He, part of an untouchable judiciary, was the independent chair of a government inquiry trying to seek out truth. What mattered was the information, not how it arrived.

‘And that’s it?’ Iona said.

‘So far.’ He did not mention the grave tone or the warnings contained in the accompanying letters from Sayyid, not wishing to alarm her further. ‘There will be more.’

‘How much more?’

‘I don’t know.’

‘How are you going to proceed?’

‘I’m trying…’ he began.

‘You’ve not always been the strongest of men, Francis.’