UK-Mauritius Chagos Islands Deal Sparks Legal and Ethical Storm

On May 22, 2025, UK Prime Minister Sir Keir Starmer signed a landmark agreement to transfer sovereignty of the Chagos Islands to Mauritius, ending more than half a century of British control over the disputed Indian Ocean archipelago. The deal, which includes an annual payment of £101 million to Mauritius and allows the UK to retain a 99-year lease on the strategically vital Diego Garcia military base, has ignited fierce controversy both in Britain and among Chagossian communities worldwide.

Strategic and Financial Stakes

The agreement is designed to safeguard the continued operation of the US-UK military installation on Diego Garcia, a base that has played a central role in Western security operations across the Middle East, Africa, and South Asia for decades. The UK government, backed by US President Donald Trump, has argued that the arrangement is “absolutely crucial for our defense and intelligence, and thus, for the safety and security of the British populace,” according to Prime Minister Starmer. The base will remain under joint UK-US control for at least 99 years, with Britain paying Mauritius a multi-billion-pound sum over the course of the lease.

Legal Hurdles and Chagossian Opposition

The deal’s path to ratification was abruptly complicated when a High Court judge issued an injunction just hours before the planned virtual signing ceremony, following a lawsuit brought by two Chagossian women, Bernette Dasse and Bertrice Pompe. The claimants, both British citizens and descendants of the islands’ original inhabitants, argued that the agreement had been reached without meaningful consultation with the Chagossian community, many of whom were forcibly exiled by the UK in the 1960s and 1970s to make way for the Diego Garcia base.

Chagossian leaders, including displaced activists like Bertrice Pompe and Misley Mandarin, have condemned the deal as a betrayal, asserting that it disregards their rights as British citizens and jeopardizes their hopes for return and restitution. “Returning to the islands will become even more difficult once Mauritius assumes control,” said Dasse, reflecting widespread fears that the transfer could further marginalize the Chagossian diaspora.

International and Political Backdrop

The agreement follows years of mounting international pressure on the UK to end its “colonial administration” of the Chagos Islands. Both the United Nations and the International Court of Justice have called for the territory to be returned to Mauritius, which was separated from the archipelago by Britain in 1965, just before Mauritian independence. The deal also comes amid concerns in Washington and London over Mauritius’s growing economic ties to China, with some British officials warning that the arrangement could pose future security risks.

Public Debate and Next Steps

Critics, including opposition politicians and former defense officials, have questioned both the financial wisdom and the ethical foundations of the deal, with estimates suggesting the total cost to the UK could reach up to £30 billion. The Mauritian government, meanwhile, has voiced reservations about the terms, particularly regarding sovereignty over Diego Garcia and the economic structure of the agreement, but has signaled willingness to proceed following further negotiations.

The High Court’s injunction was lifted later on May 22, allowing the signing to go ahead, but the agreement still requires ratification by both the UK and Mauritian parliaments before it can take effect. The fate of the Chagos Islands—and the rights of its displaced people—remains at the heart of a contentious debate over colonial legacy, national security, and international law.