This paper develops a critical perspective on the ‘new’ governance of science and the environment which is increasingly evident in practical attempts to build more constructive relations between science and democracy through hybrid ‘analytic – deliberative’ processes. The focus is on recent institutional and participatory experiments in the governance of nuclear waste, specifically the work of the UK Committee on Radioactive Waste Management and the trialling of a novel participatory, multicriteria, options appraisal tool called Deliberative Mapping undertaken by the authors as part of this process. Drawing on these attempts to build relations and make connections between citizens, specialists, stakeholders and policy makers, radioactive wastes, and possible courses of action for their long-term management, the methodological performance of analytic – deliberative practices and the contextual influences that frame and govern them is evaluated. The paper demonstrates powerful framing effects operated at the level of specific participatory practices, procedural politics surrounding the design of ‘new’ governance institutions, and institutional behaviour linked to wider politics of environmental risk and energy futures which narrowed down and marginalised particular discourses, knowledges, meanings, and forms of expression. Unless these often tacit power relations are acknowledged, accounted for, and exposed by all involved, but especially vested interests, analytic – deliberative institutions may well undermine public trust, credibility, and legitimacy rather than promote these democratic virtues as is widely claimed.