The British government is moving to hold its ground after President Donald Trump voiced renewed opposition to the UK’s plan to transfer control of the Chagos Islands to Mauritius, reopening a long-running geopolitical dispute centered on sovereignty, colonial legacy, and the future of a major US military base. Prime Minister Keir Starmer is standing by the agreement, despite Trump branding it an act of “great stupidity” following earlier signals of American approval.
Britain has governed the Chagos Islands, officially known as the British Indian Ocean Territory, since 1814 after seizing them from France during the Napoleonic wars. For much of the 20th century, the islands were administered jointly with Mauritius, but London separated the archipelago shortly before Mauritius gained independence in 1968. The move was designed to facilitate the construction of a US military base on Diego Garcia, a decision that led to the forcible removal of around a thousand Chagossians, descendants of freed African slaves, many of whom resettled in Mauritius and the UK.
The Diego Garcia base has since become a cornerstone of US and UK military strategy in the Indo-Pacific, hosting B-52 long-range, nuclear-capable bombers and supporting operations across the Middle East and Asia. Its strategic importance has only grown amid concerns over China’s expanding regional influence, making any change to the islands’ status a sensitive issue in Washington.
Mauritius has long argued that it was compelled to give up the Chagos Islands as a condition of independence, despite receiving £3 million in compensation at the time. Its claim has gained significant international backing, culminating in a 2019 United Nations General Assembly vote overwhelmingly supporting Mauritian sovereignty. That position was reinforced by a 13–1 advisory opinion from the International Court of Justice, which found Britain’s continued administration unlawful. The sole dissenting judge was American.
Negotiations to return the islands began under a Conservative government in late 2022 and were continued by Labour after its election victory. Jonathan Powell, a former senior aide to Tony Blair, was appointed to oversee talks, while human rights lawyer Philippe Sands played a central role on behalf of Mauritius. The deal was announced in October 2024 following discussions with then Mauritian prime minister Pravind Jugnauth, though progress slowed after a change of leadership in Mauritius and the re-election of Trump in the United States.
Under the agreement, Britain would formally cede sovereignty to Mauritius while securing long-term guarantees for the Diego Garcia base. The UK would pay Mauritius £101 million annually for 99 years, amounting to £34.7 billion in nominal terms, according to government actuarial figures. Additional provisions include £45 million a year for 25 years to support economic development projects in Mauritius and £40 million to establish a trust fund for displaced Chagossians. A 24-nautical-mile buffer zone would surround Diego Garcia, and Mauritius would be barred from hosting foreign security forces on the outer islands.
When the deal was unveiled, it had the backing of President Joe Biden’s administration and was reportedly helped along by US diplomats. Trump initially appeared open to the arrangement, telling Starmer during a White House meeting that the US would likely “go along” with Britain’s decision. However, skepticism persisted among some Republicans, including Secretary of State Marco Rubio, who warned the agreement could open the door to Chinese intelligence activity near the base.
Trump’s public reversal followed Britain’s criticism of his threats to annex Greenland, triggering a sharp response that cast doubt on Washington’s continued support. Despite the outburst, senior UK officials insist US counterparts remain privately supportive of the deal and that Trump’s comments do not reflect a formal policy shift.
The agreement has been signed by Britain and Mauritius but still requires ratification through legislation currently nearing completion in parliament. In theory, the bill could still be withdrawn, a point previously acknowledged by David Lammy, now deputy prime minister, who has said US approval is essential given shared military and intelligence interests. Nonetheless, Downing Street has dismissed Trump’s intervention, insisting Britain’s position is unchanged and maintaining that the United States ultimately supports the treaty.
As the legislation moves toward royal assent, the dispute highlights the fragile balance between historical accountability, strategic necessity, and alliance politics, with the future of one of the world’s most sensitive military installations once again caught in the crosscurrents of transatlantic tension.
