‘You won’t be able to work here. Not for a while at least.’ He still thought the Setter land should be treated as a crime scene. ‘When were you planning to leave?’

‘I thought I’d stay until after Mima’s funeral,’ Sophie said. ‘I decided when I heard what had happened. Hattie would like me to be there for that.’

In Utra Sandy was in a state of terminal panic. Joseph was nowhere to be seen. His mother was ironing a shirt for him and there was a pile of underpants on the kitchen table. Evelyn was obviously proud that her son had been chosen for the mission but was ratcheting up the anxiety. Edinburgh she could understand. Michael had been to college there and lived there. It represented sophistication. London was a different world, alien and violent. A place of hooded gangs and foreigners.

‘You’ll only be away a night.’ Perez took a seat.

‘Where will I stay?’

‘I’ll get Morag to book somewhere for you. And I’ve fixed up for you to meet Hattie’s mother in her home. It’s in Islington. Not far from the Underground. I’ll show you a map. She’s been told about her daughter’s death. Don’t worry, man. This time tomorrow you’ll be on your way back into Sumburgh.’

I’m not sure I can do this. He didn’t have to speak the words. Perez knew what he was thinking.

Evelyn finished ironing the shirt and hung it on a hanger on the door. She folded up the ironing board and propped it against the wall. Then she left the room with the underpants in one hand and the hanger in the other. They could hear her banging around in Sandy’s bedroom. She obviously considered him incapable of packing for himself.

‘Look,’ Perez said. ‘The woman’s a mother who’s just lost her daughter. That’s all you have to concentrate on. Forget about what she does for a living. Imagine how Evelyn would be feeling if your body was washed up on the shore.’

‘Guilt,’ Sandy said after a pause. ‘She’d be wondering what she could have done to prevent it.’

‘And Gwen James will be feeling just the same. You don’t want to make her feel bad about what’s happened. She’ll be guilty enough without you adding to it. Your role is to get her to talk about her daughter. Don’t ask too many questions. Just give her time and the sense that you’re really listening to her. She’ll do the rest.’

‘Couldn’t we suggest she fly up here? Then you could talk to her.’ Sandy had the air of a man desperately clutching at straws.