British music-theatre works of the 1960s and early 1970s largely avoided direct engagement with contemporary political topics. Intriguing in this light is Michael Hall’s recent proposition that Brecht’s music theatre set the terms for younger British composers’ experiments with the genre. Brecht proved a complicated model, however, because of composers’ anxieties about music’s capability to convey sociopolitical messages, and their reluctance to accord popular music a progressive function. The entanglement of Vietnam War activism and rock music forms the backdrop for analyses of two works that do address Vietnam directly: Anthony Gilbert’s The Scene-Machine and George Newson’s Arena (both 1971)–both of which also pass pointed comment on different popular-music traditions. Both works highlight the difficulty in emulating Brecht’s model in an era when the concept of ‘the political’ was being significantly redefined, and the cultural gap between activist cadres and the wider population was unprecedentedly visible.