This thesis describes an investigation into the changing professional practice of educational psychology services in England and Wales with particular reference to the consultation meetings held between educational psychologists and teachers in the schools they visit. The study uses sociocultural and activity theory models and research to structure and guide the analysis and in particular utilises a developmental work research methodology. As part of the investigation a historical-genetic account of evolving EP services describes their progress, the contradictions and underlying psychological paradigms governing practice since the beginnings of the twentieth century. A second phase of the research describes and analyses some of the working practices of EP services based on a national survey conducted in 1998 in England and Wales utilising data from 92 Local Education Authority Educational Psychology Services. The final phase of research considers the mediating artefacts, activity levels and contradictions that form important elements of the meetings between EPs and teachers. The study concludes that role of educational psychologists historically and currently is heavily restricted by their employment basis and the resulting enforced focus upon children with special needs. The use of sociocultural and activity theoretical approaches is highly recommended as a theoretically rich and creative paradigm. Developmental work research methodology, although in its infancy, provides a flexible but robust framework for structuring the recursive research process.