You shoot up out of your seat. ‘My Lord. I object most strongly. I’m sure I don’t need to state it.’

‘Yes, yes, Mr Pettigrew. Mrs Linux, you must give evidence of fact. What did you see with your own two eyes?’

‘I saw the mistress was afraid, sir! But when I went to the master about what was happening, he said only that the pair of them were to be left alone. That was the day of their soirée.’

‘Can you tell us what happened on the night of the soirée?’

‘Charles came down to the kitchen to say the prisoner was causing a commotion, so I went up. I was just in time to see her threaten Mrs Benham. She went very close to her and shouted, “This is death.”’

‘“This is death.” You’re sure?’

‘Quite sure. She said it twice. And some of the ladies were so overcome they had to withdraw to the smaller parlour, so I told Charles to take her up to the attic, where she couldn’t cause any further trouble. We should have sent for the constable straight away, of course. I wish we had. But we still had to see to the guests. We were a long time seeing everybody out, making the house secure. And when I went to speak to the master, he said we weren’t to send for anyone, that he’d spoken with the prisoner himself.’

She sucks in a breath. ‘Just after midnight, I went upstairs to make sure the front door was on the latch. I saw . . . her . . . crossing the landing above, up on the third storey, walking towards Madame’s bedchamber. It was dark. I saw only the shape of her. But she seemed distressed. She cried out. Though I could not hear what she said.’

‘You’re sure of the time?’

‘The guests had all left by ten, the master and mistress had gone up soon after. I checked the clock at that time, and I checked it again when I saw her. I called out to her, but got no answer. Well, it was so very like those other times when I’d caught her wandering around up there at night . . . that it ate at me. I asked Mr Casterwick what he thought we should do. “Go up,” he said, “and speak to the master again.” I decided I would, just to make sure. I went up. And that’s when I saw blood –’

‘Where?’

‘Spots of it on the stairs. On the landing just – just outside the library. I –’

She stops, blows into a white kerchief, says she wishes she didn’t have to speak of it.

‘Yes,’ says Jessop. ‘Yes.’ He puts one hand on his hip, making a bat wing of his gown. All the patience of a terrier at a rat hole. ‘Take your time,’ he says gently. ‘Some things are beyond description, Mrs Linux. Nevertheless, such things are the business of the Old Bailey.’