I thought about her as a newborn, how tiny and beautiful she’d been. Doug and I had treated her as though she was made of the finest glass, we had barely been able to contain our happiness in those early weeks. We had waited so long for her, had been through so much, and now there she was, so utterly perfect, we could scarcely believe our luck. And then little by little, as the months and years had passed, the doubts had crept in.

I must have sat there for more than an hour, watching as the lights of the scattered villages grew gradually stronger as the darkness gathered. From a distant church I heard a bell toll nine. My thoughts chased each other. My rage towards Hannah had been instantaneous, the thought of her hurting Toby triggering something primal and instinctive within me. I didn’t know how we could continue now, how I could ever trust her around my little boy again.

At last, cold and exhausted, I turned back towards home. When I reached my street I hesitated at our gate and took a gulp of air to steady myself. There was nobody about; no sound from the other houses, an eerie stillness in the air. When I let myself in, the hall was in darkness. I stood and listened. Had Doug gone to bed? Suddenly I heard a faint sound coming from the kitchen. A creak of a chair, perhaps a sigh. I crept nearer and pushed open the door. There, sitting at the table, was Doug. The only light in the room was the one that glimmered dimly from the oven’s hood.

I whispered his name but he didn’t look up, so I edged a fraction closer. ‘Doug?’ Filled with a sudden, nameless fear I asked, ‘Has something happened? Is it Toby? Talk to me!’

He shook his head. ‘Toby’s asleep.’

Quietly I sat down next to him. I saw that he had been crying and instinctively I put my arms around him. I think it was the first time we’d touched in months.

At last he began to speak. ‘When you left the house, I looked around at Hannah and the expression on her face … she looked so … happy. She was smiling, Beth. Actually smiling. And when she caught me looking at her it was as though she flicked a switch.’ He put his head in his hands. ‘Toby told me, he told me that she’d pushed him.’

I noticed that his hands were trembling and I reached over and took one in my own. ‘He said she told him to go and find you, and when he got to the top of the stairs …’ He looked at me, his eyes full of horror. ‘She could have killed him.’

‘I know,’ I said.

‘But why?’ he said desperately. ‘Why is she like this? Is it something we’ve done?’