I would have woken up. I would have heard him creep down the stairs. I would have told him that we loved him, no matter what he did.

The police say there was no evidence of forced entry that night. And no sign of a struggle. Billy wasn’t smothered in his bed and carried out of the house. He left of his own free will. Did he come to Mum’s to look for me, then carry on walking when there was no answer at the door? Did he head for a friend’s house and run into trouble en route? Did someone offer him a lift and then—

I drop the book and press my hand to the side of my head as a dark thought creeps into my brain.

‘No.’ I say the word aloud, to try and block it out. ‘He’s not dead.’

Billy’s alive. He ran away because he felt ashamed, unloved and rejected. He’s hiding out with a friend. He’s seen the TV appeals but he’s still angry, still hurt. Or he’s sleeping rough and hasn’t seen the appeals. He thinks we don’t care enough to come after him. But it’s been six months. Surely after this long he’d have got in touch? He knows how much I love him. He wouldn’t put me through this kind of torment. The only reason why I haven’t heard from him is because—

‘No!’ I say it again. ‘No! No!’

‘Claire?’

‘No!’ I won’t believe that. I won’t.

‘Claire?’ The voice is louder this time and I screw my eyes tighter shut.

‘No! No! No! No!’

‘Claire!’ I feel a heavy hand on one shoulder. ‘Claire, stop it! Stop it! Stop shouting.’

Mark is crouched in front of me. He’s wearing his suit trousers and a white shirt. The top button is undone and his chin is speckled with stubble. ‘What are you doing? Why are you shouting?’

I stare at him as his lips continue to move but I can’t make sense of the words that come out. It’s as though someone has woken me from a nightmare and there is a glass wall between me and reality.

‘Claire. Oh God, Claire.’ He pulls me into his arms and the scent of his aftershave fills my nostrils; a sharp citrus note against the stench of cigarette smoke. Mark hasn’t smoked for years. He must have started again on the sly. ‘Claire, I’m sorry.’ He runs a hand over my hair, then does it again and again; firm strokes from the crown of my head to the nape of my neck. ‘I’m sorry we argued last night. And I’m sorry I didn’t reply to your texts. I was so angry and I needed to cool down.’