As with other parts of the public sector, policing has had to confront the principles and processes attached to new public management. This paper examines the impact of police performance management on the ‘occupational professionalism’ of British policing actors with a particular focus on organisational units concerned with criminal investigation. Based on qualitative empirical research on two major police forces in England and Wales, the paper arrives at three main conclusions. First, there appears to be a clear impact of police performance management, with its instruments of standardised operational procedures, performance monitoring and strengthened internal accountability, on the professional autonomy given to police actors. This takes the form of what others have seen as a shift from ‘occupational professionalism’ to ‘organisational professionalism’. Second, despite this overall trend, tensions and professional rivalries remain between police frontline officers, supervisors and middle managers around the perceived virtues and practices of performance management. In particular concerns are expressed at various levels over the dangers of ‘short-termism’ in police decision-making. Third, and building on this finding, varied modes of professional adaptation to the police performance regime have occurred in which some sectors, notably those involved with high profile serious criminal investigations, have worked to win professional space and exploit a hierarchy of prestige in order to actively interpret and shape agendas. We conclude that this situation is akin to the ‘managed professionalism’ found amongst many other public service professions.