This thesis explores the tensions present in left-wing projects of renewal in the 1970s and 1980s by examining the activism of one city; Sheffield. It finds that behind the 'Socialist Republic of South Yorkshire' lay a more complex set of relationships between activists from different movements, strands of activism, and local government. It sets out Sheffield City Council's attempt at a new left-wing politics, its form of 'local socialism,' and explores how the city's wider activism of trade unionism, women's groups, peace, environmentalism, anti-apartheid, anti-racism, and lesbian and gay politics was embraced, supported, restricted or ignored by the local authority. Despite deindustrialisation and contemporary discussions of the decline of class politics, there was a persistence of class and a dominance of the labour movement in Sheffield. Unsurprisingly archival evidence, oral histories, and photographs point to tensions between class and identity politics. Yet, the focus of this thesis on how a number of new social movements and identity-based groups operated in one place, and its detailed analysis of the sites, methods, and relationships of activism has revealed the extent to which tensions existed, not only between class and identity, but between the different subjectivities represented in new social movements and identity politics. In this way, Sheffield's activism sheds light on the wider British left, showing the resilience of class-based politics and how popular notions of renewal were limited by conventions of solidarity.