The man she later learned was Dr Gill held a white paper cup to her mouth and tipped in two blue pills, then held up another of water to wash them down.

“What did you give me?” she asked, holding the pills behind her teeth.

“They’ll help you to calm down and think straight,” said the doctor.

She swallowed hard, the pills sticking in her throat despite the water, a dry, bitter taste. But the panic was lifting. The woman had gone.

“You’re safe, Mrs Tranter. Come out of the bath now.”

She wasn’t going to hand the babies over to anyone so they pulled her up as best they could and helped her step down from the bath onto the floor. Through the open bathroom door, she could see that the curtain, which had been drawn around the cubicle where she’d seen the woman, was back against the wall, exactly where it had been all day. The dawn had bloomed and bathed the room in buttercup yellow.

Everything was clean, surfaces spotless but nevertheless she thought she could detect a damp smell of mildew. Strong hands led her back to bed, past the chair where the woman had been sitting. No, where she thought she’d seen the woman sitting. As she shuffled past, with a baby son gripped in each arm, the nurse and the security guard holding her upright, she saw, she thought she saw, three silverfish spiralling out from the centre of the pale green vinyl seat in an almost synchronised wheel. She heard a clattering, a rapid tick-ticking sound of hundreds of tiny insect feet, which she surely must have imagined, and they disappeared over the edges of the chair and into its crevices.

* * *

“Lauren? Are you OK?” Patrick’s voice was distant, as if heard through a wall. The ward and the people in it had dissolved slightly, back into blocks of smudged colour.

A thought occurred to her. If the woman with the basket was real, she might come back again. No one had stopped her, no one saw her. Not the nurses, not the patients. After DS Harper had left this morning, Lauren had asked Mrs Gooch, tentatively, if she’d seen anyone on the ward in the night who shouldn’t have been there. The other woman had shaken her head slowly and given a long and ponderous “no”, implying that even the question was insane. “I heard you, um, shouting,” said Mrs Gooch. “That was what woke me up. I couldn’t really see what was going on, because the curtain was pulled across, but there wasn’t anyone suspicious here, I’m quite sure of that. This is a secure ward. Are you … OK now?”

“I’m fine,” Lauren had said, hearing the tremor in her own voice, smiling to cover it up. Mrs Gooch had cleared her throat nervously, and although Lauren wanted to ask her about whether she heard the singing, she sensed that any more questions would only make Mrs Gooch more uncomfortable.