Until recently, a medical qualification was required for senior public health posts in the UK National Health Service. Since 1997, the new Labour government has expressed its intention to take public health 'out of the ghetto' and to develop multi-disciplinary public health. In particular, it has announced the creation of a new senior professional role of specialist in public health equivalent to the consultant in public health medicine, and open to a range of disciplines. This paper asks 'what is really going on with the policy and practice of multi-disciplinary public health in the UK?' The answer draws on recent debates in the sociology of the professions, in particular the theoretical perspectives of Freidson (Profession of Medicine: a Study of the Sociology of Applied Knowledge, Dodd, Mead & Co, New York, 1970; Professional Powers: a Study of the Institutionalization of Formal Knowledge, University of Chicago Press, Chicago, 1986) and Larson (The Rise of Professionalism: a Sociological Analysis, University of California Press, Berkeley, 1977) concerning the 'professional project', Foucault's (Ideol. Consciousness 6 (1979) 5) notion of 'governmentality' and Harrison and Wood's (Public Admin. 77 (1999) 751) concept of 'manipulated emergence'. Key characteristics of the professional project are 'autonomy', the profession's ability to control its technical knowledge and application, and 'dominance', control over the work of others in the health care division of labour. Although useful as an explanatory framework for the period 1972-1997, the concept of the professional project does not easily explain the process of change since 1997. Here Foucault's concept of governmentality is helpful. Governmentality entails all those procedures, techniques, mechanisms, institutions and knowledges that empower political programmes. Professions are part of the process of governmentality, and their autonomy is always contingent upon the wider political context. Thus public health doctors have not abandoned the professional project; they have simply accepted the political reality that the boundaries need to shift rapidly from a politically unsustainable medical/non-medical distinction to one between those with and without expert knowledge. The concept of manipulated emergence helps explain why, having expressed a commitment towards multi-disciplinary public health, the government has not supported its policy more fully.