This article reviews the approaches that the four countries of the United Kingdom – England, Scotland, Wales and Northern Ireland – have taken in recent years for organising, regulating and defining social work. Social work is one of the policy areas that have been devolved to the constituent countries. This has brought extensive organisational changes, multiple policy initiatives and a proliferation of regulatory and advisory agencies. The article focuses on the attempts by these official bodies to define social work, treating the United Kingdom as a case study of the tensions of specifying what social work is and what it should be. The various attempts expose the strains and overlaps between the different agencies, and a bigger struggle to contain and control social work. The article highlights four key dimensions in the enduring debates: values–roles, social–individual, care–control and public–professional.