I used to sometimes feel as if I might fall from the edge of the world. It would happen in the middle of the night, without warning and nobody would notice. The idea didn’t frighten me: I’d given up on being afraid and begun saying I was depressed; and for some reason I hadn’t picked up an interest in alcohol, or drugs to compensate. Somehow I accepted that I would simply, if awfully, vanish. Then, in a scene like one of those in films where the film jerks to a halt and everything freezes I realised I was wrong. It felt as if I was clinging to guard-rail at the edge of the world, a metal post buried in concrete like one running along a sea wall, in a storm, waves rising above me like horses and I had lost my footing. I stopped thinking too much in metaphors, came back to London, and got on with it. So don’t you drop off either.