This paper reports findings from an evaluation of a national continuing professional development (CPD) programme for teachers in England. Data showed that the localised implementation, opportunities for interactive learning, and "collective participation" were positive factors. Research participants reported difficulties, however, in "cascading" knowledge to colleagues and in sustaining and developing their learning. It is argued that these limitations were rooted in an inconsistent theory of learning that underpinned the programme and a failure to conceptualise teachers as "lead learners" in schools. Wider implications for the design of teachers' professional development are considered. (Contains 2 figures.)