This article examines the evolution of the United Kingdom’s relations with Francophone West African countries between 2015 and 2025 in the context of Brexit and the Global Britain agenda. Using Role Theory, it analyses how the UK sought to redefine its international role through diplomatic expansion, security cooperation in the Sahel, trade agreements, and development-oriented investments. The study finds that the UK attempted to position itself as a global developmental partner combining security, economic, and governance objectives. However, military coups, geopolitical competition from Russia, China, and the European Union, as well as limitations in the effectiveness of aid and investment programmes, constrained its influence. The analysis reveals significant role conflict, role incongruence, and role contestation between the UK’s ambitions and regional perceptions. While the UK increased its engagement in Francophone West Africa, its ability to achieve long-term objectives remained limited by insecurity, political instability, and external competition. The article concludes that Francophone West Africa has become a key testing ground for the UK’s post-Brexit foreign policy and its ambition to be recognised as a credible global developmental partner.