• This thesis examines the relationship of the ‘approved’ avant-garde culture to the ‘outsider’ culture of experimentalism. This relationship exhibits some parallels to the idea of cultural hegemony articulated by Edward Said in Orientalism and is informed by four basic aesthetic principles. These principles can be found in the work of Cornelius Cardew after he finished working on Karlheinz Stockhausen’s Carré (1959–60) and in the musical and referential concerns of the musicians, artists, and others who formed the Scratch Orchestra (1969–73). Such a difference can also be found in activities which are less usually considered to be experimental activity, particularly the post-Scratch Orchestra political and tonal composers. The thesis shows how British experimentalism embraced many features of other arts, especially those of visual arts, and uses documented compositional and performance activity (including concerts, tours, text and tonal pieces) to establish a sense of the richness and consistency of experimental music within its own cultural and aesthetic terms.