"Amid increasing interest in participatory forms of environmental appraisal and decision making, the actors shaping these new governance spaces remain understudied. This paper seeks to refocus accounts of public engagement in science onto these participatory appraisal experts, or ‘experts of community’, through drawing on in-depth empirical research that followed them through networks building up around participatory appraisal practice in the UK environmental-risk domain. A mapping of the general nature and character of this emerging epistemic community provides the context within which to analyse how it has evolved and has begun to influence policy processes in the area of radioactive waste. Prospects for studying networks of public engagement experts at the science–policy interface and wider implications for deliberative democracy under uncertainty are explored."