Well-established internationally, the current development of social work in UK accident and emergency (A&E) departments is part of a conjoint health/social care policy drive to divert older people from 'unnecessary' admission to acute hospital care on social grounds. However, from older service users' standpoint, the prime criterion for assessing A&E social work is not its powers of diversion, but its contribution to optimum health and social care. Our account indicates that A&E based social work can provide important benefits, including help with negotiating the A&E environment and readier access to social services. Nevertheless, continuing professional-service user power imbalances, together with shortages in health and social care services, undermine its positive contribution both within A&E and following discharge. Notably, under-resourced community based health and social care can lead to services implemented through A&E, swiftly unravelling. This has serious consequences for older service users facing interlinked health and social problems, and may be implicated in re-attendance at A&E.