If you go into a bar or restaurant with a cop, the first thing he does is he'll stand in the entrance, and he'll look at every single face in that room because he doesn't want to spend an hour having a drink or lunch and didn't spot some villain they've been looking for, for two years.

There's no question that ghosts exist. The big question for me is whether ghosts are simply electronic imprints left in the walls or the atmosphere of places, or whether they do actually represent something from the afterlife.

Every profession has its own culture, but the police look at the world differently to everybody else. I call it a 'healthy culture of suspicion'.

Police do get obsessed with solving crimes. You know, particularly if there's been a murder, it becomes personal for the police officer very quickly, and it gets to the family. Even after they've retired, they carry on, not letting go.

Music is an important part of my writing process.

I travel abroad constantly on book promotion and research, and the Internet is invaluable to me for accessing U.K. news in places such as America, which most of the time hasn't heard of England.

Most good police officers are very open-minded. The bad ones are the ones who are close-minded.