This paper explores the currently popular ‘Nudge Agenda’ in the field of Behavioural Economics. ‘Nudge’ is based on the idea that no choice is ever presented in a neutral way, that the behaviour of humans can be inconsistent and contradictory, and that psychological techniques can be used to influence this behaviour. This paper explores how and why nudge is being employed by the UK government at this time. The evidence base for its effectiveness in public health promotion is assessed, and the political necessity for a clear cut answer explored. This paper explores ethical issues arising with the theoretical components of these suggestions, and issues relating to the unequal application of the agenda to more vulnerable groups. A wider public health, social policy research and financial argument is also made. This paper draws conclusions about potential lessons to be learned from the gaps in current publications, and makes specific recommendations for evidence-based application and future research in this dynamic and changing area. The analysis will be of use to students of social policy, mental health and behavioural economics, as well as policy makers themselves.