He raises his plastic cup to his mouth with both hands. He drinks and licks some water across his lips. The corner of his mouth twitches again, and I catch the beat of two syllables but I can’t make out the words. He closes his eyes quickly to compose himself before he asks, “You know the date today?”

Out of habit I glance at my watch, but I know without having to look.

“Sixth of June,” I say slowly. “The anniversary of Danny’s death.”

Simon widens his eyes at me. “Twenty-one years.” He glances down at his hands, his fingers splayed in front of him, as though he needs them to calculate the number of years gone by. “Twenty-one years of reliving that day, a lifetime of wishing I was dead instead of my son.”

His voice doesn’t crack, but for just a moment his mouth becomes a thin, hard line. Grief has grown around Simon like ivy, twisting and squeezing until at last it swallowed him whole. I glance at the camera. Upton said I only had ten minutes; this might be my only chance to find out the truth.

“Simon, we need to talk about Grace.” I keep my head turned away from the camera and my voice low as I add, “Or Zoe.”

His eyes widen when I say her real name, flash with recognition before his forehead creases. “Grace?” he whispers. He won’t call her by her real name, not here. His gaze searches the boxy room around us, as though he expects to find his daughter hiding in a corner.

Without warning he stops searching, stares back at me. The left side of his mouth curls upwards again as he says, “She was always such a little thing, so small I could pick her up with one hand.” He raises his right hand to demonstrate. I fear for the imagined baby in his hand. “But I wasn’t allowed to see her. Not since everything. She said I was too dangerous to be near her.”

“Who said that? Meg?”

His eyes trace around the room again, as though his whole dead family are in here with us. At last, his eyes come back to me.

“She said after Danny that I shouldn’t be near children, that I was dangerous, that I’d hurt them even without trying. She said I pushed her down the stairs.”

“Did you, Simon? Did you push Meg?”

The corner of his mouth twitches again, as though he’s struggling with the words inside him. He can’t contain them, but he can’t release them either. Again two syllables escape, but I still can’t make out the meaning.

He starts shaking his head. “No, no,” he says, and at first I think he’s crying, but then I realize he’s shaking with laughter.

“I don’t know, I can’t remember.” He raises his hands to his head and he starts pulling his hair so hard it looks as though he could rip his scalp clean off his head.