This paper assesses the growing UK private sector in education and questions whether it is, as its supporters suggest, a valuable addition to an already diverse national system. An earlier "Perspectives" paper (Woodfield et al 2011) explored the emerging partnerships between public and private sectors. This follow-up explores the roles that the private sector providers are now playing. To understand this fully it is essential to analyse the range and type of private providers, since their different characteristics and functions mean that only some are relevant to this debate. (Contains 1 table.)