While the use of mounted police (i.e. police horses and riders) can be traced back to before the advent of the modern police service in 1829, very little is known about the actual work of mounted police from either academic or practitioner standpoints. In recent years, mounted units have come under resource scrutiny in the UK due to austerity measures. Some forces have eliminated their mounted capacities altogether, while others have developed collaborative or mutual assistance arrangements with neighbouring forces. The relative costs and benefits of the available options — maintaining units, merging and centralizing mounted resources, or eliminating them in whole or part — cannot at present be assessed confidently by individual forces or by national coordinating agencies.To address this limitation in available evidence, the Association of Chief Police Officers' Mounted Working Group commissioned a project to consider ways in which the relative value of mounted police work may be measured and understood, as well as provide evidence testing the value of mounted police in various deployment scenarios. This main report details the multi-method and exploratory research undertaken for this project, and examines mounted police in neighbourhood policing, football policing and public order policing in festival and demonstration settings. The report also includes a full account of the research activities designed to understand the costs of mounted policing, and an international survey of senior mounted police in other countries.