LONDON

Less than a year after Britain agreed to transfer sovereignty of the Chagos Islands to Mauritius in exchange for continuing operation of a strategic military base there, criticism from the US has raised questions about the deal and exposed another point of friction in US-UK relations.

Debate over the Chagos Archipelago deal resurfaced after US President Donald Trump, adamant to takeover Greenland, criticized the agreement signed by the UK and Mauritius as "an act of great stupidity."

What are the Chagos Islands?

The Chagos Archipelago or the Chagos Islands is a group of seven atolls comprising more than 60 islands in the Indian Ocean, 500 km (300 miles) south of the Maldives.

In the late 18th century, France took control of the Chagos Archipelago and Seychelles as dependencies of Mauritius, and slaves from African countries were transported to work in the coconut plantations there.

Britain took over the islands, including Mauritius, in 1814 after the defeat of Napoleon under the Treaty of Paris.

In 1965, the UK separated the group of islands from Mauritius, which claims it was forced to give them away in exchange for independence in 1968.

Diego Garcia, the largest of the islands, has since hosted a joint UK-US military base that resulted in the displacement of about 2,000 residents.

UK's deal with Mauritius

Mauritius has long claimed the islands as part of its territory. In a non-binding opinion in February 2019, the International Court of Justice (ICJ) ruled that the UK is “under an obligation” to end its administration of the Chagos Archipelago. A resolution welcoming the advisory opinion was adopted by the UN General Assembly in May the same year. Six months later the African Union also demanded the UK to end its "colonial administration" of the Chagos Archipelago.

Britain, however, claimed sovereignty over the islands, which it had designated as British Indian Ocean Territory.

Under increasing pressure, in May 2022 the UK Foreign Office opened negotiations with the East African nation on the exercise of sovereignty over the Archipelago.

After two years of talks, the UK reached an agreement with Mauritius in October 2024 to give sovereignty of the Indian Ocean Archipelago to Mauritius. A £3.4 billion ($4.5 billion) deal was signed in May 2025 that secured the Diego Garcia military base on a 99-year lease.

The agreement has not yet entered into force as it is pending domestic ratification.

Are there any legal concerns to the deal?

Along with the legality of sovereignty over the islands, the rights of the Chagossian people have always been a matter of international law.

The ICJ had found that the detachment of the Chagos Archipelago from Mauritius violated the Chagossian people’s right to self-determination.

In a statement in December 2025, the UN Committee on the Elimination of Racial Discrimination expressed "deep concern" that the deal would perpetuate longstanding violations of the Chagossian people’s rights.

The UN committee said the Chagossian community, an ethnic group of African and South Asian descent with a distinct cultural identity, was forcibly displaced from the islands to make way for the construction of the joint US-UK military base.

The UN statement's key focus was that the deal "explicitly prevents the return of the Chagossian people to their ancestral lands in Diego Garcia Island," even though it permits Mauritius to implement a resettlement program on the other islands of the Chagos Archipelago.

Since the agreement does not provide for full reparation for the harms they have endured, the committee called on both the UK and Mauritius to suspend ratification process of the agreement.

Why is US criticizing the deal?

The US had initially welcomed the May 2025 deal, branding it as "historic" and commending both the UK and Mauritius for their "leadership, vision, and commitment to ensure that Diego Garcia remains fully operational for the duration of this agreement."

The State Department said President Trump "expressed his support for this monumental achievement during his meeting with Prime Minister Starmer at the White House."

But this week, Trump, under opposition from allies for his bid to takeover Greenland, the autonomous Danish territory he says is needed to ensure national security and deter rivals China and Russia in the Arctic, said the deal represents "total weakness."

"The UK giving away extremely important land is an act of great stupidity, and is another in a very long line of national security reasons why Greenland has to be acquired," Trump said on his Truth Social account.

Will Trump's criticism affect US-UK ties?

Trump’s criticism of the Chagos Islands deal comes when the UK-US relations are already tense over a series of disputes, including US criticism of alleged worsening of freedom of speech and human rights in the UK, and a new tariff threat to allies over Greenland.

Trump’s invitation to Russian President Vladimir Putin in his Board of Peace also did not sat well with the UK, as the foreign secretary said "Putin is not a man of peace."

Besides trade, the “special relationship” between the US and UK builds on strong security and intelligence links, including a nuclear cooperation agreement and an integrated defense industrial complex.

Unlike some of US's European allies like France who have requested to consider activating a trade "bazooka" against the US, British Prime Minister Keir Starmer is treading a fine line in diplomacy and has played down the prospect of any retaliatory tariffs.

Since it could antagonize Trump, the former human rights lawyer also did not say if the US violated international law when the American military captured Venezuelan President Nicolas Maduro on Jan. 3 and flew him to New York to charge him for drug trafficking.