Policy changes have rendered the United Kingdom (UK) one of the most liberalised gambling markets globally. Product design, marketing sophistication, and industry strategies are evolving at considerable pace, posing challenges for existing regulations. Concomitantly, the extent and diversity of gambling harms are receiving greater recognition as a public health issue. Gambling regulation and the problem definition are highly contested. In 2019 the UK Government committed to reforming gambling law, initiating a formal review of the Gambling Act in 2020. However, critical analysis of UK gambling policy, including how it is formed, who seeks to influence these processes, whose problem definition and solutions are adopted, and with what consequences, is lacking, particularly from a public health perspective. Drawing on poststructural discourse theory (PSDT), the critical logics approach (CLA), and the literature on both the commercial determinants of health (CDOH) and ignorance studies, the research presented in the thesis provides a critical analysis of UK gambling policies and practices, and how these have been formed, challenged, and maintained. A range of complementary methods were used, including document analysis, stakeholder interviews, and case studies and data derived from these. The findings represent an analysis that explains the emergence and reproduction of an industry-favourable gambling policy regime and provide a detailed account as to how and why this regime has resisted transformational change, demonstrating the role of particular social and political practices that maintain the status quo at the expense of public health. The knowledge generated from this programme of research is intended to support public health practice and advocacy by opening spaces for debate, exposing what has been taken for granted and what possibilities have been concealed, by whom, how, and with what consequences. The potential application of the methods and findings to the study of other industries and their public health impacts is also explored. Through this the research aims to contribute to the wider literature on the CDOH.