In 1945, the new Labour government set about creating what it hoped would be a revolution in social conditions in the English cities; later Conservative governments continued down the same track, at least until 1979. City governments controlled education, urban regeneration, and housing; the central state provided health, and social security. This paper examines the progress, and consequences, of that attempt at large-scale, planned, social change. The Welfare State in 1945 was rooted in an industrially-based, working-class world, dominated by poverty and poor physical conditions. Over the next forty years, the values of this world were challenged by affluence, by social mobility, by de-industrialisation, by the effects of immigration and of ethnic rivalries, and by the pursuit of individual (rather than collective) solutions to social problems, while (reflexively) welfare-state institutions themselves affected the political impact of social change (for example, by amplifying ethnic rivalries around access to state-provided housing). This paper examines the consequences of these changes in social structure and values, both for the Welfare State itself, and for the Labour Party. No simple social determinism explains the political outcomes; rather, policy and social change interacted to produce outcomes which were unexpected and unpredictable. Studying these changes provides unique insights into the social and the political history of England in the forty years after the end of the War.