Access to primary health care is an important aspect of health systems in terms of their ability to address population health inequalities. For multiple reasons, since the founding of the National Health Service (NHS) and through the last several decades, access to general practice has increasingly become a policy focus in the United Kingdom. However, when I applied a broad conceptualisation of access following a review of the theoretical access literature, I was able to demonstrate that past interventions have been based on a narrow, or absent, conceptualisation of access and relatedly, have lacked a contextual understanding of the existing issues around access to general practice. As a result, past efforts have potentially worsened health inequalities by not addressing, and hence perpetuating, existing problems of access. In a time of a growing and ageing population and a developing healthcare workforce shortage, this research aimed to understand how population access to general practice can be optimised, to make the best use of available resources and improve health inequalities. To address this aim, I performed a qualitative, participatory instrumental case study of access to general practice in an area of Northwest England, consisting of the Tameside and Glossop Clinical Commissioning Group (CCG) footprint. I worked with, and employed multiple methods to understand the perspectives of, patients, carers, health service staff, commissioners, and voluntary sector workers. I applied the broad conceptualisation of access, as the interaction or fit of health services and population needs, in order to understand a wide range of people's experiences in context. The community-based project team (CBPT) that I formed early in this work met 35 times over 4.5 years to plan and execute this project with me. In total I conducted 19 semi-structured interviews, 7 focus groups, 13 observation sessions across 8 general practice sites (totalling 45 hours), and 12 observation sessions in relevant public meetings and events (totalling 26 hours). An ongoing, iterative, and abductive analysis process facilitated the purposive sampling and understanding of emerging concepts until data saturation was achieved. As a result, in this thesis, I present a novel description of access problems as a paradox of demand on general practice and unmet need in the population, which was created and perpetuated by layers of reactive, rigid rules, the undermining of continuity, and resulting extra work. I apply the understanding of the paradox, in addition to the broad conceptualisation of access, to critique the main intervention to improve access to general practice during the time of this study: seven-day extended access. I demonstrate that, like previous interventions, this politically-driven idea lacked grounding in an appropriate understanding of access and of existing problems, and continued to perpetuate the problems within the paradox, including unmet need within the population. I also apply the paradox to critique another policy trend in general practice of increasing practice size. I demonstrate that several issues within the paradox were exacerbated at larger practices, where the demand felt greater, the rules tended to be more complicated and rigid, and continuity was further undermined. I compare this to the smaller practices where the proactive approach required to address needs within certain groups of the population was facilitated by a less overwhelming feeling of demand, an ability to flex rules, and a preservation of various types of continuity, both with clinicians and other practice staff, which made work more efficient. The above findings and my analysis processes enabled me to advance an understanding of access called 'people-centred access,' in which access is the fit of human factors of people on both the service and population sides of interactions. Applying this advanced understanding of access, I demonstrate how to optimise population access to general practice and improve population health by directly addressing the longstanding and complex issues with the paradox of access problems. Subsequently, this work has important implications for people and practice, policy, and research around how to approach this important issue to achieve improved population health.