They live at the edges of our vision, vanish when we turn to look. Though we are diligent in our searching and meticulous in our research, they keep slipping into the shadows. We are not who you think we are, one told me once; I asked him, politely, to explain, but he would not.

It is rumoured that the taxi drivers might know how to find them, the hairdressers too. So we are heading for the laybys, the train stations, the nightclubs, and all those glass-fronted shops full of mirrors and blades.