The paper focuses on the cases of four aspiring CTs as they led collaborative practitioner enquiries (CPE) in two schools as part of their qualification programme. The central question is what does the practice of CPE offer in relation to professional re-formation and development? The paper draws on the work of Foucault to argue that ‘active positioning’ is in operation which appears to influence what is possible and permissible for all actors in this context. It appears that the school managers are positioned by professional socialisation processes and the policy context, to discipline and control teachers in order to meet their accountability responsibilities. In general, they position teachers as reluctant and lacking initiative, while the teachers themselves report a desire to be more proactive and actively look for ways to be so. The CTs are positioned, in an ‘in-between’ space: neither teacher nor manager. Their managers position them as exceptional, while their teacher colleagues assign them the role of ‘expert’ in relation to enquiry methods.Led in this way, CPEappears to offer a space in which the teachers and CTs are able to construct new professional identities and contribute to curriculum change, in spite of managerial constraints.