Addressing the quality of services provided in Emergency Departments (EDs) has been a central area of development for UK government policy since 1997. Amongst other aspects of this concern has been the recognition that EDs constitute a critical boundary between the community and the hospital and a key point for the identification of social care needs. Consequently, EDs have become the focus for a variety of service developments which combine the provision of acute medical and nursing assessment and care with a range of activities in which social care is a prominent feature. One approach to this has been the establishment of multidisciplinary teams aiming to prevent re-attendance or admission, re-direct patients to other services, or speed patients through EDs with the aim of providing improved quality of care. This study, carried out between September 2007 and April 2008, was the first UK national survey of social care initiatives based in EDs and aimed to determine the objectives, organisation, extent, functions, funding and evidence on outcomes of such interventions. Eighty-three per cent of UK Type I and II EDs responded to the survey. Approximately, one-third of EDs had embedded social care teams, with two-thirds relying on referrals to external social care services. These teams varied in their focus, size and composition, leadership, availability, funding and permanence. As a result, the unintended effect has been to increase inequities in access to social care services through EDs. Three further conclusions are drawn about policy led, locally-based service development. This survey adds to international evidence pointing to the potential benefits of a variety of social care interventions being based in EDs and justifies the establishment of a research programme which can provide answers to key outstanding questions.