The transformation in the purposes, instruments, and conditions for the deployment of coercion was a central aspect of the modernization of Western European states during the long nineteenth century. Nowhere is this transformation as evident as in the emergence and diffusion of public, specialized, and professional police forces at the time. In this article, we employ automated text analysis to explore legislative debates on policing in the United Kingdom from 1803 to 1945. We identify three distinct periods in which policing was highly salient in Parliament, each of them related to more general processes driving the modernization of the British state. The first period (1830s–1850s) was marked by the institutionalization of modern police forces and their spread across Great Britain. The second period (1880s–1890s) was dominated by Irish MPs denouncing police abuses against their constituents. The third period (1900s–1940s) was characterized by discussions around working conditions for the police in the context of mounting social pressures and war-related police activities. Whereas the first and third periods have attracted much scholarly interest as they culminated in concrete police reforms, the second period has not been as central to historical research on the British police. We show, however, that policing became a major issue in the legislative agenda of the 1880s and 1890s, as it highlighted the tensions within a modernizing British state, torn between the professionalization of domestic police forces under control of local authorities and the persistence of imperial practices in its colonial territories.