This study of social enterprise in the UK is part of a pan-European comparative study. We explore the evolution of the concept in the UK and different legal forms used. We then explore the evidence of the scale of the sector, using both a definition from the European Union that is more focused on the not for profit forms, and the UK definition that includes a large proportion of private enterprises. The study explores the support ecosystem for social enterprise, and the public procurement context. The study ran workshops with key players in the sector, and the findings are presented in a concluding section on current trends and future prospects of the social enterprise sector.