This paper considers the needs of an ageing population and the implications for Human Computer Interaction (HCI) research. The discussion is structured around findings from interviews with medical and care professionals and older people. Various technologies are being successfully used to monitor for falls and other emergencies, and also to assess and manage risk. The design of this technology is currently driven by a medical model of client needs and takes little account of the social context of the home. The design challenges for HCI are to make this technology attractive, provide privacy, allow informed choice and reduce rather than increase the isolation currently felt by many older people. It is argued that the ageing population presents a fundamental challenge to HCI in the need for socially dependable systems. Socially dependable systems take account of social context, the need for sociability and are accessible to all who need them.