Britain announced on Thursday that it would relinquish sovereignty over the Chagos Islands to Mauritius, marking a significant shift in a long-standing dispute. This decision will allow the return of people displaced decades ago, while ensuring that the UK retains use of the Diego Garcia military base, jointly operated with the United States.

The agreement preserves the operation of Diego Garcia, a key airbase in the Indian Ocean, crucial for national, regional, and global security. US President Joe Biden welcomed the deal, emphasizing that it secures the base’s role for the future. “Diego Garcia is vital for global security, and this agreement ensures its effective operation into the next century,” Biden stated.

British Foreign Minister David Lammy highlighted that the ongoing legal challenges concerning the sovereignty of the islands had previously put the future of the Diego Garcia base at risk. “Today’s agreement secures this vital military base and reinforces our commitment to global security,” Lammy said.

Britain has controlled the Chagos Islands since 1814 and detached them from Mauritius in 1965, three years before Mauritius gained independence. In the early 1970s, Britain evicted nearly 2,000 residents to establish the airbase, which was leased to the US in 1966. This forced displacement has been a point of contention, with a 2019 UN General Assembly resolution stating that Britain should relinquish control of the islands and calling the displacement wrongful.

In 2016, the UK’s Foreign Ministry extended the lease on Diego Garcia until 2036, reaffirming that the expelled islanders would not be allowed to return. However, the current agreement represents a policy shift under Prime Minister Keir Starmer, who emphasized a commitment to international law. Starmer’s office stated that the agreement underpins national and global security, solidifying the UK’s stance.

Mauritian Prime Minister Pravind Jugnauth hailed the decision as a step toward decolonizing the archipelago. Despite the positive reception, some within Britain’s opposition Conservative Party criticized the move, with former foreign minister James Cleverly calling it “weak” on social media.

Under the agreement, Britain will maintain sovereign rights over Diego Garcia to ensure the continued operation of the military base for an initial 99-year period. The strategic value of Diego Garcia has been demonstrated in past conflicts such as Iraq and Afghanistan, where it served as a critical launch pad for long-range bombers.