The London High Court has rejected a legal bid to challenge the UK’s agreement to transfer sovereignty of the Chagos Archipelago to Mauritius, ruling that the case raised no new grounds. The decision removes a final domestic legal hurdle to the controversial 2023 deal, which ended decades of dispute over the Indian Ocean territory.
The challenge was brought by three plaintiffs, including Bertrice Pompe, a British national born on Diego Garcia, the archipelago’s largest island. They argued the UK government failed to consult the Chagossian community before finalising the agreement with Mauritius. Pompe had previously sought to block the deal in May 2023 but was unsuccessful. Their lawsuit targeted the Foreign, Commonwealth and Development Office, seeking to overturn the political agreement.
In her written judgment, Judge Mary Stacey recognised the “long and shameful history” of the Chagossians’ forced removal from the islands in the 1960s and 1970s to make way for a critical military base. However, she concluded the current application was a “repetition” of arguments previously examined and dismissed by English courts in earlier Chagos-related litigation. The court therefore refused permission to proceed with the claim.
The historical context is central to the dispute. After Mauritius gained independence in 1968, the UK retained control of the Chagos Archipelago. Between 1967 and 1973, the entire population of around 2,000 Chagossians was expelled to allow the construction of a joint UK-US military facility on Diego Garcia. The base has since been used for operations in the Middle East and Asia.
The October 2023 agreement, negotiated by the previous Conservative government, stipulates that sovereignty will be ceded to Mauritius. In return, the UK will secure a 99-year lease on Diego Garcia to continue hosting the military base, currently operated by the United States. The deal aims to resolve a long-standing dispute at the International Court of Justice and within the United Nations, while maintaining strategic UK-US military access.
While the ruling allows the diplomatic agreement to proceed, it does not address the broader demands of the Chagossian diaspora for the right of return and redress. Legal experts note the court’s decision reinforces the principle that domestic litigation cannot re-litigate settled matters of foreign policy. The UK and Mauritian governments are now expected to move forward with the technical implementation of the sovereignty transfer, a process anticipated to take several years. The case underscores the enduring tension between resolved state-to-state agreements and the unresolved claims of displaced former inhabitants.
