Taking as its starting point the establishment of the Standing Commission on Carers in 2007 and the launch of the National Strategy for Carers in 2008, this article explores who carers are and how demographic changes are likely to impact on carer numbers. It deduces that the need for care is likely to rise significantly in the near future and as such carer numbers will grow. It argues that future policy must take this, and the importance of carers themselves being supported, into account. The article's main focus is on a carer community that has remained largely hidden, that is, imprisoned people who are caring for other prisoners. The extent and nature of the rapidly increasing prison community is discussed with particular attention being drawn to prisoners' health. The high prevalence of poor health in prison is attributed to a complex combination of circumstances. Research (particularly co-author Julia Tabreham's PhD study 'Prisoners' Experience of Healthcare in England) is used to demonstrate that prisone [...]