Sometimes, completing a book is that great expulsion of a strange pressure that we like to dignify with childbirth metaphors but which is much more like wrapping the head of a giant tapeworm around a stick and slowly pulling all sixty feet of the bastard out of your back passage. Sometimes, like this one I just completed, it’s an act of perverse woodwork. You can see the shape of it in your head, but it’s not like sculpture, where the image is trapped inside the raw stone and needs to be revealed. It’s throwing up a whole weird rickety structure you only half-imagined, and then spending days and weeks screwing beading and architraves and batons and odd knobbly bits to the thing, banging pegs into slots you cut two weeks earlier knowing they needed something to fill them. And, finally, you’ve fitted every joint and groove, and you look up at the thing, and all you can say is, well, it ain’t art, but it ain’t falling over either.‘

Warren Ellis