To ensure effective primary prevention of skin cancer, aimed at changing behaviour in the sun, and ultimately at reducing the incidence and mortality rates from skin cancer, sufficient information needs to be known about the relationship between sun exposure and skin cancer, the effectiveness of sun protection measures, and the acceptability and uptake of protective measures by the general public. This review specifically addresses the quality and outcome of studies designed to evaluate the impact of primary prevention initiatives in the U.K. Four main areas of concern are highlighted: (i) teenage behaviour in the sun is difficult to change; (ii) fashion, in part, dictates adult and adolescent behaviour in the sun; (iii) there are practical problems related to response rates, follow-up and interpretation of self-reported behaviour; and (iv) a strategy for primary prevention in the U.K. may be falsely based on the experience and results of Australian and American programmes. Standardized methods for monitoring general population behaviour are needed in the U.K. Evaluation of interventions targeting specific groups, especially parents and young children, and the relative costs of different strategies should be reported. Primary prevention messages and strategies should be adapted to the type of ultraviolet radiation exposure experienced, and the overall low risk of melanoma, while addressing controversies on the health effects of sun exposure and sun screens.