The image of housing as the wobbly pillar under the welfare state has been widely used in recent years, and is clearly an attractive metaphor in the present period as residualisation deepens and privatisation continues. However, this paper is concerned with the early years of the postwar welfare state, when conditions for a securely founded housing service were, arguably, more conducive than they are today. Accordingly the paper focuses on policy work in the 1940s, drawing on new research on Public Record Office files, to reveal the amount of wartime planning within Whitehall for postwar housing policy, and the extent of continuity between the pre and post 1945 periods. It is shown that under the wartime coalition government there was considerably more planning for housing after the war than is acknowledged in the existing literature, and that this work shaped policy under the Labour government of 1945–51. Housing emerged as the wobbly pillar under the welfare state because of the amount of detailed wartime planning and Labour's acceptance of its analysis and prescriptions. Whereas most accounts concentrate on the size of the late 1940s building programme (and judge the government accordingly), the argument here is that to understand how housing emerged as the wobbly pillar it is necessary to look beyond quantity to the question of why a self-proclaimed socialist government failed to challenge the market dominance of housing provision.