This dissertation offers a critical and historical study of the ways in which popular music, avant-garde performance, and political life intersected within the context of burgeoning Thatcherism, the New Right, and neoliberalism in 1970–80s Britain. Drawing on archival research and interviews, I argue that the case studies considered––multimedia punk collective Crass; performance troupe COUM Transmissions; free improvisation at the London Musicians Collective; and the reggae-based “dub poetry” of Linton Kwesi Johnson––provide fresh perspective on this political-aesthetic tangle, showing not only how the nominally distinct domains of “art” and “pop,” “high” and “low” routinely came together in the 1970–80s, but that such a convergence in turn brought practices that variously reinforced or helped to counter the similarly contradictory phenomenon that Stuart Hall and his colleagues at the CCCS once called the “crisis” of the postwar welfare state. In the process, I ask: what might it mean to create an avant-garde at a moment when Thatcherism likewise trumpeted touchstone avant-garde ideals, including “do-it-yourself,” anti-statism, creativity, resilience in the face of precarity, and even countercultural resistance? If neoliberalism offered one fruitful means for Thatcherism to “manage the crisis” of the disintegrating welfare state, might comparable neoliberal criteria have given punks, performance artists, improvisers, and reggae musicians an analogous political-aesthetic toolkit? How might the making of “popular avant-gardes,” as I call the aforementioned coalescence, have contributed to this complex of issues? The answers to these questions are multiple, and in seeking them I build on recent work in music studies, avant-garde theory, cultural studies, art criticism, media theory, gender studies, and black studies––in ways that ultimately exceed a concentration on popular avant-gardes or Thatcherism exclusively.