Biological diversity is declining globally. The current national environmental policies that many countries around the globe have adopted and are implementing have not halted biodiversity loss as expected. This is also happening in several European peripheral areas that constitute important “biodiversity hotspots” for the numerous species, habitats and ecosystems they host. Among these biodiversity hotspots, the Overseas Territories (OTs) of the United Kingdom (UK) represent important areas for academic investigation, particularly at this moment. The recent exit of the UK from the European Union will imply a net drop in financial contributions made available for the UK’s OTs. This adds to the limitations and constraints imposed upon those territories by their geographical isolation and small scale, as shown by the case of Saint Helena. The article provides insights on the role of policy resources in the analysis of public policies. It, then, focuses on biodiversity policy in St Helena under various angles: relations with the UK, organisational arrangements within the island, the legislative framework and its execution for the protection of biodiversity. Finally, the article discusses the major challenges faced in the development and implementation of Saint Helena’s biodiversity policy with an emphasis on the role of tangible and intangible resources. It concludes with a set of recommendations tailored around the specific case of Saint Helena but also applicable to other OTs.