In Brest, at the far end of Brittany, on winter mornings, people go to work in the pitch dark. They keep the same time as Paris and Berlin, but their city is further west than most of Britain, where the clocks are set an hour earlier. It is a concrete illustration of the uneasy way in which Brittany, a long, low, folded peninsula of granite and slate, about the same size as Wales, fits into the centralised, Continental power that is modern France.