Abstract
The United Kingdom Education Reform Act of 1988 has brought major change to primary teaching. In contrast to their previous generalist role, from 1990 primary teachers were expected to acquire sufficient knowledge of all nine National Curriculum subjects and religious education to teach 5-11 year-olds at the requisite level. National surveys have revealed primary teachers' uncertainty about their competence to teach all subjects. This article examines the impact of two 20-day subject courses on the professional development of primary teachers. One course in particular had a powerful effect on the teachers' thinking, classroom practice in all subjects, and sense of professionalism. This is an important study as it shows the complexity of teachers' professional knowledge and the value of particular kinds of in-service training.