Despite an obvious and growing need, there has historically been scant provision of social care and social work in prisons. Thus although the 2014 Care Act gave local authorities in England responsibility for identifying, assessing and meeting adult prisoners’ social care needs, little was known about the number of prisoners eligible for support, the extent of their needs or how best to meet them. Against this background, this paper reports the findings of two national surveys of local authority managers undertaken in 2016 which found that upwards of 1,800 prisoners with social care needs were identified in the first year, of whom almost 1,600 received an assessment and approaching 800 were deemed eligible for the provision of care and support. Whilst specialist social care staff (primarily social workers) were widely engaged in prisoner assessments, many local authorities had delegated their responsibility for identifying prisoners with social care needs to prison healthcare staff, and there was considerable variation in the way that social care and support were delivered. A number of implications for social work practice and research were identified, including a need for greater active case finding and further evaluation of the impact of the emerging arrangements on prisoners’ outcomes.