Chagos Islands

What does each side say?

Mauritius says the Chagos Islands have always been part of its territory. Mauritian leaders agreed to the separation at talks in London in 1965. Mauritius says they had no real choice, because Britain tied the separation to independence. In 2024 Prime Minister Pravind Jugnauth said the handover deal would "complete the decolonisation of our republic." The Mauritian government calls its sovereignty "non-negotiable."

For decades the UK said the Mauritian ministers had consented in 1965, and that no court should rule on the dispute without Britain's agreement. The Starmer government said court rulings had put the base's legal status in doubt and that only a deal with Mauritius could secure it. Conservative leader Kemi Badenoch called the deal an "immoral surrender." Some critics warned that Mauritius could let China in. Prime Minister Ramgoolam denies this and says Mauritius would not let China take control of the islands.

Chagossians are divided. Olivier Bancoult's Chagos Refugees Group backs Mauritian sovereignty. Other Chagossians, many of them living in the UK, want to return under British rule. Two Chagossian women, Bernadette Dugasse and Bertrice Pompe, argued in court that Chagossians had not been consulted. A judge blocked the treaty's signing on May 22, 2025, and another judge lifted the order the same morning.

Why were the Chagossians removed?

The United Kingdom removed the Chagossians between 1967 and 1973 to make way for a US military base on Diego Garcia. Chagossians visiting Mauritius in 1967 and 1968 were refused passage home. The last Chagossians left Peros Banhos atoll in 1973. Most were taken to Mauritius and the Seychelles. Britain told the United Nations that the islands had no permanent population, only contract workers. Foreign Office papers made public in a 2000 court case called this a "fiction."

The Chagossians, then called the Ilois, descended mainly from enslaved Africans and Indian laborers brought to work on coconut plantations. Britain paid Mauritius 650,000 pounds in 1973 and 4 million pounds under a 1982 agreement. Most recipients signed forms in English, many with a thumbprint, giving up further claims. Chagossians say most could not read them. Many lived in severe poverty. The British government has since called the removal "shameful and wrong."

Chagossian leader Olivier Bancoult has fought in British courts since the late 1990s for the right to return. He lost at the House of Lords by three votes to two in 2008. On March 31, 2026, the BIOT Supreme Court quashed the rule that no one has a right to live in the territory. The ruling is suspended while the UK appeals.

What does the 2025 treaty say?

On May 22, 2025, British Prime Minister Keir Starmer and Mauritian Prime Minister Navin Ramgoolam signed a treaty transferring sovereignty of the Chagos Islands to Mauritius. The two governments had announced a political agreement on October 3, 2024. Ramgoolam, who took office in November 2024, reviewed it before signing.

Under the treaty, Mauritius leases Diego Garcia to the UK for 99 years, and the UK can extend the lease by 40 years. The UK would pay an average of 101 million pounds a year. The UK government puts the net present cost at 3.4 billion pounds. Nothing can be built within 24 nautical miles of Diego Garcia without UK consent. Mauritius may resettle Chagossians on the outer islands but not on Diego Garcia. Britain would also fund a 40 million pound trust fund for Chagossians.

The treaty has not entered into force. The UK needed a law and an update of its 1966 base agreement with the United States. The Diego Garcia Military Base and British Indian Ocean Territory Bill passed the House of Commons on October 20, 2025, and the House of Lords amended it in January 2026. The bill fell when the parliamentary session ended in April 2026.

Why does Trump oppose the Chagos deal?

The US government backed the treaty when it was signed in May 2025. On January 20, 2026, President Trump called the handover "an act of great stupidity." He wrote that China and Russia had noticed "this act of total weakness." The UK government replied that court decisions had put the base under threat. In early February he backed the deal again after talks with Prime Minister Starmer. On February 18 he wrote that Britain should not "give away Diego Garcia." Press Secretary Karoline Leavitt said the post should be taken as the policy of the Trump administration.

On April 13, 2026, Foreign Office minister Stephen Doughty told the House of Commons that an update to the 1966 base agreement had become "impossible to agree at political level." Andy Burnham replaced Starmer as prime minister in July 2026. On September 22 Trump told Burnham the treaty was a "terrible deal." The next day Defence Secretary Wes Streeting said the deal could not go ahead as drafted without US support and that payments to Mauritius would not be made "at this stage."

Mauritius calls its sovereignty "non-negotiable." In October 2026 Prime Minister Ramgoolam told the UK that Mauritius would "take the legal route" unless the deadlock was resolved quickly.

What is Diego Garcia used for?

Diego Garcia is a joint US-UK military base about 1,800 km south of India's southern tip. Its runway, about 3,660 m long, can handle B-52 and B-2 bombers. US bombers flew from the base to strike Afghanistan in 2001 and Iraq in 2003.

In February 2008 Foreign Secretary David Miliband told Parliament that two US rendition flights carrying detainees had refueled at Diego Garcia in 2002. CIA Director Michael Hayden confirmed the stops. The British government had earlier said, relying on US assurances, that no such flights had landed there.

In March 2026, during the Iran war, Britain let the United States use its bases, including Diego Garcia, for strikes on Iranian missile sites. Britain described the strikes as defensive. Iran then fired two intermediate-range ballistic missiles at Diego Garcia, according to US officials cited by the Wall Street Journal. One failed in flight, and a US destroyer fired an interceptor at the other. Neither hit the base.

About 2,000 people, mostly military personnel and contractors, are usually on the island. Families may not come, and the BIOT administration says the territory is "not a tourist destination."