The paper describes a case study of the development and implementation of a policy to monitor teachers’ classroom practice in a secondary comprehensive school in Wales, UK. The change process is interpreted from an affective standpoint to explain how the experience of feelings and emotions shapes organisational practice. In particular, the interpretation illustrates how affective experience may influence the distinction between espoused and in use theories, which may in turn have an effect on individual and organisational resistance to change and the success of the implementation. Differences between espoused and in use theories may increase both organisational anxiety and resistance in a self-sustaining cycle. We argue that when the anxieties and emotions of organising in schools are allowed to surface in the change process and are reflected upon, the espoused and in use theories are more likely to correspond and organisational anxiety and resistance to change to decrease.