Fortunately, she had found a surprising array of new hobbies over the Internet, things that with his technical knowledge he had been able to help with. A bedridden woman thirty years ago would have been able to do nothing but watch TV. But now she was able to roam the world, talk to people and even earn a kind of living. As the kettle boiled, he picked up the teapot and warmed it carefully, then poured boiling water over a scoop of lapsang souchong leaves. He then picked up a large package, the size and weight of a bale of toilet rolls, which had come from South Korea yesterday, the usual Monday delivery. He broke open the package and pulled out a crisply wrapped cellophane packet, one of a hundred within. This was a new flavour. He couldn’t read the Korean script, but the picture of what looked like a sea vegetable made it clear. He wondered how his mother would get on with it. He looked at his watch. She would do a little practice this morning and then was due on screen this afternoon at what she called Chinese dentist: two thirty. It was her little joke, one that she never ceased to find amusing.

There was one final letter, a small, neatly handwritten envelope, posted in Buckinghamshire on Friday. It was addressed to his mother using her old married name. That was weird. After the divorce the whole family had gone back to her maiden name. He took it up to her, with her tea, and went downstairs.

The scream he heard from her a minute later had him racing back up to see what was the matter.

Detective Inspector Claire Mulholland had set off earlier than usual for her shift at Surrey Police’s Mount Browne headquarters. After setting a breakfast for her teenage kids, she had to give her plasterer husband Baz a lift to his first day on a new contract, while his van was being serviced. ‘I’ve been booked for a week on this job,’ Baz said, as they skirted the high brick wall encircling the Holdersham Estate near Walton-on-Thames.

‘I didn’t realise you meant here. So you’re working for the sheikh?’

‘Yep. It’s billionaires’ alley round here. It’s a bit of a rush job, and they’re paying double time. It’s got to be done by this time next week. Jakes recommended me.’

‘Ah. He’s the eccentric one, isn’t he?’

‘He’s all right. Hadn’t seen him for months until this. Dead easy to work with, if a little boring. Never get a peep out of him. He’s got them things in his lugs all day. Classical music. He let me listen to it once. Sounds like an orchestra tumbling down a hill.’ He laughed.