‘You can’t go yet! It’s not even properly morning,’ she cried. ‘Stay! Please stay, Clara. Did you sleep at all? Let me make you some breakfast. I really don’t think you should be alone …’

But Clara barely heard her. ‘I have to go. I have to speak to the police, see what I can do to help. I can’t just hide out here, while Luke is …’ tears filled her eyes and angrily she swiped them away. ‘I need to help find him.’

She drove home as dawn broke over London, the new morning filling the city with a pale, golden light. She saw barely a soul as she slipped through the silent streets: the occasional homeward-bound reveller, a fox streaking between parked cars; grey puddles of sleeping forms sheltering in shop doorways. The sun was rising as she crossed the Thames, staining the water red and orange, its light catching on the glass and steel of the buildings lining the river. Her body ached from lack of sleep but her nerves were raw and jangling, her mind alert. She would go home and shower, then go to the station to speak to Anderson. She put her foot on the accelerator, her eyes focused grimly on the road ahead.

Parked in her usual spot a short distance from her flat, Clara found she couldn’t move. She sat for some minutes willing herself to get out, but the thought of returning home to sit alone with Anderson’s words running through her brain filled her with despair. Impulsively she turned the key in her ignition and drove on.

Twenty minutes later she sat at Mac’s kitchen table, his face ashen as she described Anderson’s phone call. ‘My God,’ he said, staring at her in disbelief.

‘Do you … do you think he’s dead?’ she asked.

‘No!’ he said sharply and in his agitation got up and began to pace around the room. ‘Of course I don’t.’ He went to the kettle but instead of putting it on, stood for a long time, his back to her, unmoving.

‘Mac …’ she said.

He swung round to look at her, his face white, his eyes wide and frightened.

‘Are you OK?’ she asked. ‘Come and sit down. You look like you’re going to be sick.’

‘It’s just, I wasn’t expecting this,’ he said. ‘I thought … I thought he would be home by now, that he would be OK.’

‘I know,’ she said, ‘I’m so frightened. What if he’s dead, Mac, what if this bloody maniac has killed him?’