It was Elizabeth. I leapt forward and smashed the STOP button with my sticky fist. The scene wobbled and froze, but didn’t disappear, although the girl was gone, eclipsed again by Dr Harmer’s shoulder. I wheeled around angrily. ‘You don’t sneak up like that!’

Her hands were pressed to her belly, which still protruded like a younger child’s. ‘I feel poorly,’ she complained.

‘You shouldn’t be out of bed. Go back to your room. I’ll be there in a minute.’

‘What are you watching?’ She was looking at the screen, at her mother’s breasts, anonymous but clearly exposed.

‘Nothing. None of your business.’

She belched – a belch that had a retch folded up in the end of it. ‘I think I’m going to be sick.’

‘You can’t be sick here. You need to go the bathroom.’

But there wasn’t time. She dropped and puked with unnatural force. Dark liquid dripped off her chin and soaked the carpet. She was shivering all over, pale and slightly sweaty. Her nightie was thin and white and printed with faded hearts, and the ridge of her spine showed through the fabric when the retching arched her back. I went to her, and put my hand on her shoulder. The fabric was clinging to her skin, a fearsome heat powering through it. Little chunks of half-digested mush sat on top of the carpet’s pile, and a white pip that could have been what was left of her Warfarin tablet.

‘You silly girl,’ I said. ‘What did you do?’ But I already knew. She’d drunk the tea Dominic had made. I’d poisoned her and she was going to die.

A line of spit slid from her lip to the floor. We heard the key turn in the lock downstairs, and then the grandfather clock on the landing struck the hour and started to chime. It must be ten, I thought. They’d said they’d be back by ten. Whatever control Elizabeth had been maintaining finally dissolved, and she wailed for her mother.

‘Don’t shout!’ I hissed. ‘Go down! Go down and see her!’

But now she was really crying, breaking off her sobs of ‘Mum!’ to retch again.

Mrs Harmer called back, faintly, ‘Elizabeth? Are you all right?’