When I was growing up in a small town on the south-east coast of Ireland in the 1950s, London seemed as far away as Samarkand. We had seen it in the movies, of course — The Lavender Hill Mob, The Blue Lamp, The Ladykillers — but we knew that was all made up. The real city had to be seen to be believed. Yet when I went there for the first time as an eager 18-year-old, I was disconcerted. London looked exactly like London. It was only when I lived there that it became a foreign place.