This thesis draws attention to the overlooked period of English avant-garde activity that arose in response to the Situationist International (SI, 1957-1972). I attempt to consolidate the continued literary, political and artistic relevance of the disparate manifestations of English Situationist practices, while reflecting more broadly on the Anglicisation of Continental avant-garde traditions. The thesis contributes also to the ongoing re-evaluation of the SI through its peripheral and international permutations. The thesis presents an historical narrative in four stages. The first follows the formation of the Surrealist Group in England and its transformation into Mass- Observation. This activity in the Thirties is both prolepsis to and prehistory of the English Situationist tradition, which begins at the thesis's second stage, in the early Sixties, with the novelist and cultural organiser Alexander Trocchi, one of the first British members of the SI. The third stage introduces the short-lived English Section of the SI and its immediate precursor and successor groups of the late Sixties, all of whom undertook a cultural translation of the SI's project. The thesis's final stage identifies contemporary manifestations of what I argue is an English Situationist poetics, which exists independently of self-identifying avant-garde groups. Interwoven through my historical narrative are investigations of three recurring problems: the problem of ‘Englishness', and its perceived incompatibility with Continental avant-gardism; the problem of influence, whereby neo-avantgardism is dismissed as the hollow repetition of early twentieth century formations; and the Situationist problem of the radical aesthetic object's subsumption to a commodity economy. I offer readings of novels, films and visual materials; of tracts, manifestos and journal debates; and of theorists (especially Rancière) whose perspectives on history and political aesthetics are productively dissonant with those of the SI. Anglicised Situationist practices, I propose, are valuable precisely for their contestation of and movement through Situationist theory.