1. The UK’s decision to leave the EU has far-reaching implications for agriculture and fisheries. To ensure the future sustainability of UK agricultural and fisheries systems, we argue that it is essential to grasp the opportunity that Brexit is providing to develop integrated policies that improve the management and protection of the natural environments, upon which these industries rely. 2. This article advances a stakeholder informed vision of the future design of UK agriculture and fisheries policies. We assess how currently emerging UK policy will need to be adapted in order to implement this vision. Our starting point is that Brexit provides the opportunity to redesign current unsustainable practices and can in principle deliver a sustainable future for agriculture and fisheries. 3. Underpinning policies with an ecosystem approach, with explicit inclusion of public goods provision, and social welfare equity were found to be central to the success of this endeavour. Recognition of the needs of, and innovative practices in, the devolved UK nations is also required as the new policy and regulatory landscape is established. 4. Achieving our proposed vision will necessitate drawing on best practice and creating more coherent and integrated food, environment and rural and coastal economy policies. Sustainable prosperity should and can form the core of future post-Brexit environmental policy thinking and our findings demonstrate the “bottom-up” and co-production approaches that will be key to the development of more environmentally sustainable agricultural and fisheries policies.