The creation of a colonial police force in Tanganyika after the First World War and its elaboration over the next four decades is described, as are its role in the attempted assertion of urban order and its relations with the Dar es Salaam public. The force was a central component in the colonial state's efforts to assert control over the urban arena. Lacking both resources and legitimacy it was only partially effective in this regard, with intermittent enforcement of colonial legislation being the norm. More concerted efforts to supervise the urban African population at a time of rapid urban growth in the post-Second World War period led to a deterioration in – already poor – police-public relations, which served further to undermine colonial authority.