The relationship between local government and public participation is a problematic one. Taking the UK as an example, it is evident that, despite 40 years of experimentation with public participation initiatives, there has been little impact on local policy processes. While a range of plausible explanations can be found for this state of affairs, no overarching theoretical framework is available to organize them. The purpose of this paper, therefore, is to offer just such a framework of analysis by utilizing and developing the conjectures approach originally used by Klijn and Skelcher (2007). Four conjectures, developed from the UK experience, are presented. These are the transitional, incompatibility, instrumental and resistivity conjectures. The paper concludes by discussing the implications for research and for policy.