Chagos Islands: Why has U.K. handed it over to Mauritius after 50 years? Premium

Mauritius wins sovereignty over Chagos Islands from UK, leasing Diego Garcia naval base, amid political and legal battles.

Story so far: Mauritius won a strategic victory on May 22, 2025, when the United Kingdom (U.K.) officially handed over sovereignty of the Chagos Islands after finalising the political treaty agreed to in October last year. Under the deal, the important naval and bomber base on Diego Garcia — one of the archipelago’s largest island, operated by U.S. forces, will be leased by the U.K. from Mauritius which will maintain sovereignty over the region. 

Terming the deal as vital to British security, Mr. Starmer said that it was the only way to maintain the naval base’s long-term future. He added that if U.K. had not agreed to the deal, the legal challenges mounted by Mauritius would open avenues to China or any other nation set up their own bases on the outer islands or carry out joint exercises near its base. Mauritius has agreed to initially lease Diego Garcia to the U.K. for £101 million a year for 99 years. 

The British are letting go of the islands after 50 years, after initially buying it for £3 million in 1968.

In 1793, the French established coconut plantations in the islands off approximately 1000 km from Maldives. A set of eight atolls i.e. ring-shaped islands, totalling sixty islands — Peros, Salomon, Nelsons, Three Brothers, Eagle, Danger, Egmont and Diego Garcia along with Mauritius and Seychelles were handed over to the British empire in 1814. Initially, the islands were inhabited by the African slave workers and Asian natives who spoke French-based languages. However, the population changed as contractors from Mauritius and Seychelles arrived in the 1950s and 1960s to work, but not own lands or houses. 

In 1965, these islands were constituted as the British Indian Ocean Territory (BIOT) along with the islands of Aldabra, Desroches and Farquhar — which were later ceded to Seychelles during its independence in June 1976. As the British empire began shrinking, U.K. envisaged the use of Chagos island as a military base. Roping in the United States (U.S.) as a partner in 1967, the U.K. allowed the U.S. to use Diego Garcia for defence purposes initially for 50 years and the agreement would remain in force for further twenty years, (beyond 2016) unless terminated by either nation. 

A year later, on March 12, 1968, Mauritius gained freedom from the British and U.K paid a £3 million grant in recognition of the detachment of the Chagos Archipelago from Mauritius and amongst other legally binding undertakings. Between 1968 to 1973, plantations across the islands were shut and the BIOT administration forcibly removed the inhabitants to make way for the military base in Diego Garcia. Inhabitants have been exiled from the island giving them a choice to move either to Mauritius or Seychelles. In 1971, BIOT passed an ordinance making it unlawful for a person to enter or remain in BIOT without a permit and allowed those remaining to be removed. 

Estimated to have exiled around 10,000 Chagossians, the British paid £6,50,000 in the 1970s and a further £4 million in 1980s to Mauritius for resettlement. In 2002, the U.K. changed the British Nationality law allowing Chagossians who had BIOT citizenship to automatically become British citizens. Currently, a small community of Chagossians reside in Crawley, Sussex, and another in Manchester, still fighting for their right to return to their native land.