The Behavioural Insights Team (BIT) has led in the promotion and adoption of behavioural science research in public policy. This comment, by Liam Delaney of the Geary Institute (UCD), addresses a number of issues that must be faced by BIT and the wider behavioural public policy agenda as the field becomes institutionalised and normalised within public policy internationally, in particular issues of ethics and professional codes. As work in this area is increasingly conducted at scale, it is important to develop a framework for considering the ethical and practical implications of the application of behavioural science to policy. Liam Delaney’s commentary on this development can be found here .