The aim of this chapter is to contribute to our understanding of the relation between popular music, festival and activism by focusing on a neglected but important area in festival history in Britain, what can arguably be seen as its originary decade, the 1950s. So I chart and interrogate the 1950s in Britain from the perspective of the rise of socio-cultural experimentation in the contexts of youth, some of the ‘new ... old’ (Morgan 1998, 123) sonic landscapes of popular music, social practice and political engagement. I foreground the shifting cultures of the street, of public space, of this extraordinary period, when urgent and compelling questions of youth, race, colonialism and independence, migration, affluence, were being posed to the accompaniment of new soundtracks, and new forms of dress and dance. Some of the more important popular culture events where these features manifested, performed and celebrated themselves, produced what I see as a significant phenomenon: the youthful gathering of the festival, the surprising splash and clash of street culture (McKay 2007).