As I write, it is exactly a year since the desolate banlieues of France erupted in an orgy of violence, on a scale which had not been seen for generations. At the time, these riots were blamed on social exclusion. Since then, it has become clear that the rioters are not just 'immigrants' or 'youths', but are first and foremost Muslims. When they set light to a car, their cry is often: 'Allahu akhbar!' ('Allah is great!') The violence, moreover, is endemic and ubiquitous. In 2005, there were 110,000 incidents of urban violence, including 45,000 vehicles burnt out. This year,...