Contracting Decolonization. Implementing the Chagos Advisory Opinion Through UK-Mauritius Agreement

Abstract

This article examines the implementation of the International Court of Justice’s 2019 Advisory Opinion on the Chagos Archipelago through the 2025 UK–Mauritius Agreement. It situates the Agreement within the broader trajectory of Mauritian decolonisation, characterised by sustained engagement with international adjudication alongside diplomatic negotiation. After outlining the historical and legal background to the Chagos dispute, the article analyses the Advisory Opinion and its legal consequences, including its reception by the United Nations General Assembly. It then offers a detailed assessment of the Agreement, focusing on sovereignty, security arrangements relating to the Diego Garcia military base, resettlement of the Chagossians, environmental governance, and financial provisions. While acknowledging significant criticism, particularly concerning limitations on resettlement and participation of affected communities, the article argues that the Agreement represents a rare example of the effective operationalisation of international judicial determinations through treaty-making. It concludes that the Chagos settlement, though imperfect, illustrates the potential of law-informed diplomacy in resolving protracted disputes.