Nicholas stepped forward quickly, picked up the knife and took it outside to Vowell. The old servant stared at Isabel in horror through the doorway. The painting was now scored with innumerable slashes, spaces where pieces of plaster had fallen revealing the lath behind. A tiny stream of plaster dust trickled down. I saw that the section of the painting she had attacked most fiercely, now almost entirely obliterated, was her mother’s face.

I looked at Nicholas, who was pale and breathing hard. Then I knelt beside Isabel. ‘Mistress Slanning?’ I touched her shoulder lightly. She flinched, huddling further away from me, as though she would squeeze herself into the floor, clutching at her injured arm.

‘Mistress Slanning,’ I said gently. ‘You have cut yourself, your arm needs binding.’

The sobbing ceased and she turned her head to look at her arm. Her expression was bereft, her hair wild. She looked utterly pitiful. Lifting her eyes, she met mine briefly before shuddering and turning her face away. ‘Do not look at me, please.’ She spoke in an imploring whisper. ‘No one should look at me now.’ She took a deep, sobbing breath. ‘He was innocent, our stepfather, a good man. But we did not see it, Edward and I, till it was too late. Our mother was cruel, she left that Will so we would quarrel, I understand it now. It was because both Edward and I loved the painting so. Mother never wanted us to visit her, but I would come sometimes, to see the painting. To see our father again.’

I looked at their mother’s empty chair, facing what was left of the painting, the embroidery still lying on the seat.

‘He died so suddenly, our father. Why did he leave us? Why?’ She wept again, the tears of a lost child. ‘Oh, Edward! I drove him to that unclean act. All these years I could have confessed; the old faith allows that if you repent and confess your sins it is enough, you are forgiven. His faith did not allow even that. But I – ’ her voice fell to a whisper – ‘my hardened heart would not allow me to confess. But it was both of us together did that thing, both of us!’

I jumped at the sound of a sharp knock at the door. I heard Vowell and another voice, and then Vincent Dyrick strode into the room, gown billowing theatrically behind him, his lean hawk face furious. He looked at Nicholas and me, at Isabel weeping on the floor, then gaped at the wrecked painting.

‘Shardlake! What have you done? Why is my client in this state?’

I rose slowly to my feet, my knees cracking and my back protesting in pain. Isabel was looking at Dyrick; it was the same puzzled, otherworldly look Edward had worn in the Tower, as though she barely understood who he was.

‘Ask her,’ I answered heavily.