The guard winced. ‘May I stop just a moment, sir? My leg pains me.’

‘Of course.’

‘A Frenchie soldier ran it through with a half-pike in Boulogne last year.’

‘I am sorry. I know it was a fierce campaign.’

‘They gave me this job afterwards. I won’t be going soldiering again. I’m all right to go on now, sir, thank you.’

The door was opened by a guard and we walked down that dreadful stone staircase, slick with green algae once we passed under the level of the river. The light came now from torches, stinking with smoke. At the bottom was a barred door which I remembered. My escort called out and a hard, unshaven face appeared behind the bars.

‘Yes, sir?’

‘This gentleman has permission to look at the log.’ Sir Edmund’s note was passed through the bars. The man on the other side looked at it, then closely at me, before turning back to my escort.

‘You’re to wait and take him back?’

‘Yes.’

There was a clank of keys, and the heavy door opened. I went through, into a stink of damp, and entered a long vestibule with bare ancient stone walls, a row of cells with barred windows along its length. It was cold down here, even in high summer. I observed – strange the things one notices at such times – that the layout of the central vestibule had been changed: the desk which was its only furniture was larger than the one that had stood there five years ago, and had been positioned against the wall to allow more space for people to pass. It was covered in papers and a man sat behind it. I saw a large open ledger.

The guard who had let me in looked me up and down. ‘Your purpose, sir?’ he asked in a voice which was quiet but not respectful.

‘Matthew Shardlake, Serjeant at Law.’ I told him the story of the dubious witness. Lying was not easy under his hard, watchful eyes.

‘Well, if Sir Edmund agrees,’ he said reluctantly. ‘But you’re to write nothing down, only look through quickly for the name you seek.’

‘I understand.’

‘My name is Ardengast. I am in charge here.’

Without further comment he led me to the desk. The man sitting behind it was a big, middle-aged fellow in a leather jacket, with an untidy straggling beard. He sat up straight as we approached. Ardengast said, ‘This man is to see the logs from June the twentieth to July the fifth, Howitson. Looking for a witness in a case.’

The man in the leather jacket frowned. ‘It’s not to do with—?’

‘No. Some law matter.’ Ardengast waved dismissively. He glanced again at Walsingham’s note. ‘The name is Edward Cotterstoke. I don’t remember him.’

‘Nor I.’

‘That is the point,’ I said. ‘I think he was lying about being here.’