This paper sets out to describe and explore experiences gained in the course of ten years with a non-blaming, nonadversarial learning methodology, as applied in the context of the policing of major events, where at the request of a host, peers gather data during events as they occur and a one-sided focus on errors is avoided. This peer review methodology appears to contribute to organisational learning in three different ways: hosts receive informed and constructive feedback, reviewers gain additional experience and insights and the exchanges taking place in the course of or following the reviews (e.g. in seminars) contribute to the identification of good practices and development of professional norms. Experiences show that the interactions taking place between participants also facilitate mutual understanding and cooperation. Interestingly, quite apart from the products obtained through the methodology, the peer review process itself proved to foster reflection and learning.