Stalin was experimenting with telepathy in the 1930's. Winston Churchill had a paranormal office, trying to get people to travel out of their bodies and see behind enemy lines in the Second World War. And the Pentagon... The X-Files is based on a real department in the Pentagon, that's still there now. Pretty much every government, probably as far back in time as we can go, has one. And the police will quite often - and when I say often, I mean often - they will go to mediums if all else fails in the enquiry.

Almost every officer is going to put their life on the line at some point in their career.

There's a really classic cliche every time you switch the TV on - you see cops arguing. I have spent a day a week for many years in the presence of police and I have never seen them argue. It's a military hierarchy. They do what they're told. There's no bickering.

There are an awful lot of readers who won't pick up a book if they think it's got anything horrific in it, or paranormal or whatever.

I guess a lot of police keep their sanity by developing black humour.

If you and I took a walk down a shopping street in Jo'burg or Cape Town or London, we see two guys looking in a shop window, we think, "Oh, they're wondering what they're going to buy." A cop looks at them and thinks, "Why are they standing there? Are they doing a drug deal? Are they going to mug someone? Are they going to rob the shop?"

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.