This thesis sets out to understand the nature of non-professionals as they engage in extended roles and develops a sophisticated understanding of the drivers and causes of extended roles. It therefore, uses healthcare assistants (HCA) in healthcare in the NHS as an illustrative case, to address the theoretical concerns of the research. These questions ask, first what are extended roles, why do they persist among non-professionals and whether policy can explain why extended roles occur. The contributions offered are based on the analysis of the labour process of HCA work and inter-professional boundaries and how these limit extended roles. It also offers an assessment of how Agenda for Change (AfC) policy working in an environment in which resources are constrained and the factors that lead to these outcomes. It offers the theory of psychological contracts and introduces the notion of third party obligations as part of the reason why extended roles within non-professionals persist.