The journey of global Britain: British foreign policy adaptation in the context of Brexit.

The United Kingdom's departure from the European Union reignited long-standing debates about its international role, crystallised in the political vision of Global Britain. While frequently presented as a novel post-Brexit initiative, this thesis argues that Global Britain represents the rearticulation of deeper, post-1945 narratives about Britain's global role, adapted to the political and strategic conditions of the Brexit era. The research addresses the question: How has the idea of Global Britain influenced UK foreign policy in the context of Brexit? It identifies a gap in the literature on British foreign policy analysis by integrating a constructivist focus on ideas with a longitudinal examination of political discourse and institutional uptake.

Adopting a constructivist theoretical framework, the thesis conceptualises Global Britain as an ideational construct capable of shaping foreign policy by providing strategic narratives, framing decision-making, and embedding within institutions. The research design combines qualitative content analysis of government speeches, parliamentary debates, policy documents, and think tank reports with elite interviews involving policymakers, advisers, and intellectuals engaged in foreign policy debates. This mixed-methods approach enables the tracing of Global Britain across multiple sites of production and contestation, from its pre-referendum antecedents to its operationalisation and subsequent adaptation.

The analysis finds that under Theresa May and Boris Johnson, Global Britain primarily functioned as a rhetorical and strategic device rather than a coherent, actionable policy doctrine. It was employed to manage political uncertainty, legitimise Brexit, and signal continuity in global engagement, but its implementation was fragmented and often reactive. The concept's persistence nonetheless reflects its utility as a flexible repository of Britain's post-imperial ambitions, accommodating shifts in emphasis between soft power, trade diplomacy, strategic alliances, and commitments to security and defence.

This thesis contributes to the study of foreign policy by examining the tension between idealistic goals and policy pragmatics. By systematically reconstructing the genealogy, evolution, and operationalisation of Global Britain, the thesis advances constructivist foreign policy analysis by demonstrating how ideas operate simultaneously as normative frames, causal beliefs, and political instruments. It offers an empirically grounded account of post-Brexit foreign policy-making, highlighting the tension between discursive ambition and policy execution, and refines methodological approaches for tracing the life-cycle of foreign policy ideas across time and institutional contexts. In conclusion, the study suggests that the United Kingdom's global position will remain fluid, thereby enhancing understanding of its dynamic role in the international landscape.