The health service reforms in the United Kingdom have posed significant problems for the carrying out of the public health function. The increasing size of populations for which health authorities are responsible makes the formation and maintenance of strong community links difficult. An attempt to broaden the membership of the Faculty of Public Health Medicine beyond members of the medical profession has failed to achieve consensus support, and academic departments are highly variable in their working links with the NHS. The creation of a separate public health service for the country has become a possibility. Behind these structural problems lies the lack of a commonly understood and agreed theoretical basis within the specialty. It is argued that an understanding of the role and functioning of the specialty as well as the real determinants of health is important to the achievement of improvement in the health of the population. The NHS reforms have created an opportunity for public health practitioners that if not seized may not be recreated for some time.