“The best horror films all deal with common, sometimes primal, fears, such as fear of the dark, of violence, of harm coming to a loved one, of realising you don’t really know the person you’re closest to, of knowing we are all capable of both great good and great evil. The way I always thought about it was, if I fill the film with some of my own fears, like some of the ones I mentioned, it’s bound to frighten at least some other people too.”