This paper examines the fracture points, or areas of weakness and failure, in social policy formation – from agenda setting through to policy formation and its legitimisation. It suggests why it is that despite clearly identified severe and widespread problems, which have been shown to drive and maintain poverty and which are also clearly associated with marginalisation and vulnerability, policy makers may still fail to generate adequate responses. Social policies have been selected as the focus of this study because they are generally weakly addressed by the development and poverty policies of both donors and developing country governments. Also includes case studies that examine the barriers to effective policy responses to the problems of marginalised and vulnerable groups. The multiple deprivations experienced by some of these groups increases their likelihood of being not only poor, but chronically poor.