In the area of musical production, Modernity has produced a series of debates about the legitimacy of new types of cultural production. From Dada to Gangster rap, the aesthetics of shocking the elite (épater le bourgeois) have been central to many artistic and cultural currents. Even the more shocking of cultural expressions have normally been able on the course of time to join the mainstream museums, auction rooms and lecture theatres of established culture. This paper will explore aspects of legitimacy in modern British popular music, taking examples from the whole of the twentieth century, from Music Hall, through rock and punk to rap and Banghra.