This paper summarizes the findings of studies of schools where initiatives were under way to develop provision for pupils experiencing difficulties in learning, and discusses the theoretical significance of these findings for our understanding of how mainstream schools can be made more inclusive. It submits the 'consensus thesis', which has been influential in recent research in this field, to a critical examination in the light of this evidence. It shows that teaching staff in the schools investigated used contrasting discourses of learning difficulty. The various types of relationship which were found to occur in practice between different constituencies of staff are described and analysed. In the light of this analysis, it is argued that the consensus thesis stands in need of revision. An alternative theoretical account of the relationship between contrasting discourses of learning difficulty and the dynamics of the school development process is proposed.