While more flexible models of service delivery are being introduced in UK health and social care, little is known about the impact of new roles, particularly support worker roles, on the work of existing practitioners. This action research study aimed to explore the impact of one such new role, that of interprofessional care co-ordinators (IPCCs). The general (internal) medical service of a UK hospital uses IPCCs to provide support to the interprofessional team and, in doing so, promote efficiency of acute bed use. Using a range of methods, mainly qualitative, this action research study sought to explore the characteristics and impact of the role on interprofessional team working. While the role's flexibility, autonomy and informality contributed to success in meeting its intended objectives, these characteristics also caused some tensions with interprofessional colleagues. These benefits and tensions mirror wider issues associated with the current modernisation agenda in UK health care.