‘But it must be! The same person who broke into your flat, who took those photographs …’

For the briefest moment Clara considered telling Rose about Luke’s affair, that she was washing her hands of her son, that he had hurt her too much to care about his whereabouts any more. But even before the thought was fully formed, she knew she never would. Because despite everything, despite all that he’d done, she couldn’t do it, not to Luke, and especially not to his parents. After all, it was hardly their fault that any of this had happened. ‘I’m going to get on the Tube now,’ she said instead. ‘I’ll phone you as soon as the police get in touch. Try to stay strong, Rose. We’ll find him. I promise.’

Sitting on the Northern Line a few minutes later, Clara brooded over Rose’s distress. Her mind wandered to a weekend in Suffolk a year or so before. It had been the day of the village fete, an event organized entirely by Luke’s parents, to raise funds for a little local girl with leukaemia. There had been stalls and games, live music and dancing, and the whole village had come along, a joyful atmosphere of community and goodwill in the air. Clara had watched as Rose had danced energetically to the band, while a smiling Oliver had organized tug-of-war contests and run the coconut shy. Despite the weeks and weeks of hard work, the time and money that had gone into organizing the event, she saw how they brushed off all congratulations and thanks with self-deprecating modesty. It was only when the parents of the girl for whom the fete was in honour approached and hugged them both that Clara saw how touched and relieved they were by the day’s success.

As her train drew into Old Street, Clara got up, reflecting bitterly at how cruel life was. Why was it that bad things seemed to happen to those who least deserved it? Hadn’t Rose and Oliver suffered enough? She stepped out on to the platform, resolving that she would do everything she possibly could to help Luke’s parents find him.

Mac was waiting for her on the street outside her building when she arrived. He was leaning against the wall, watching her warily as she approached. He raised his hands in a gesture of surrender. ‘I just wanted to see how you are,’ he said.

She sighed, too tired to turn him away. ‘Come up.’