A series of community-level trials undertaken in the United States over the past 10 years established the effectiveness of an HIV prevention intervention that systematically identifies, recruits, trains, and engages the popular opinion leaders (POLs) of a population to serve as behaviour change endorsers. Recently, several investigators reported unsuccessful attempts to implement peer education programmes for men who have sex with men in the United Kingdom and raised questions about whether peer-based programmes are effective or feasible. However, POL is a theory-based and very specialized intervention, and the UK peer education programmes did not incorporate many of POL's core or essential elements. Consequently, they were not evaluations of POL. In this article, core elements of the popular opinion leader model are presented; interpretations are made of possible reasons for the discrepant findings of the UK peer education and US POL interventions; and practical issues for applied programme development are discussed.