This article explores the growing body of professional and academic support for Multi-disciplinary Practices (MDPs) which combine the provision of legal, accounting, financial, and other 'professional' services. In doing so, it traces the development of MDPs in the UK and assesses the leading claims which have been advanced in favour of these 'one stop' providers. It is suggested that support for MDPs is located within the emergence of a new professional paradigm which places a high premium on quality of service and the resolution of complex problems and is based on a narrow conception of the public interest which is closely if not solely associated with promoting consumer welfare. This, itself, is rooted in a deregulatory vision of the world - that is, the view that the breaking down of barriers (professional, legal, and cultural), which restrict competition and impede consumer choice, is in the 'public interest'. The article challenges these views, arguing that many of the alleged consumer benefits which are said to flow from the formation of MDPs are at best speculative and that, in any case, a proper conception of the public interest is one which extends beyond a narrow concern for consumer interests.