Public actions that summon and assist police officers are vital for the effective and equitable functioning of the criminal justice system. Such acts of cooperation link informal and formal mechanisms of social control. They also reflect the legitimacy of the police. This paper reports the findings of a probability sample survey investigating public trust, institutional legitimacy and cooperation with the police in London, England. We find that the readiness of individuals to cooperate with the police is associated with their trust in police procedural fairness and the legitimacy they invest in the police. This replicates prior US-based research in the UK for the first time, but we also highlight some predictors of public cooperation that have hitherto gone unexamined. Linking police legitimacy and cooperation to perceived collective efficacy (confidence that local residents will intervene on behalf of the collective good), concerns about disorder, and authoritarian positions on the perceived loss of discipline in society, we use Bourdieu’s notions of field and habitus to highlight the role that the social position of the police plays in generating public cooperation. Police legitimacy is shaped by its location in the social ‘field’ of policing and the web of relationships that link organization and citizen.