Notwithstanding the notable public interest cases that advance the rights of disadvantaged groups in Ireland, and the positive impact that some prison law cases have had, the rights of people in prison remain under litigated. Previous research by IPRT identified that there is a need for an increase in public interest litigation to advance the rights of people in prison in Ireland. Using mixed method research methodologies (doctrinal research and 26 semi-structured interviews), this report identifies and examines the barriers and issues that arise in public interest prison law in order to shed light on this topic and to identify areas for reform. In doing so, the research illustrates a web of inter-connected problems that inhibit prisoner rights issues from being addressed in a legally effective way that protects the rights of those affected. These barriers include, and are not limited to, difficulties in accessing Civil Legal Aid (including operational barriers within the Civil Legal Aid and Legal Aid-Custody Issues Schemes), blocks in accessing legal information and legal representation, the general difficulty in prison law litigation, and deference to State authority.