What is the Chagos Islands deal? Everything you need to know as Sir Keir Starmer signs agreement

The UK has vowed to press ahead with its Chagos Island deal despite Donald Trump accusing Sir Keir Starmer of “a big mistake.”

The often outspoken U.S. leader took to his social media platform to criticise Starmer, despite the US Department of State saying it “supports the decision of the United Kingdom to proceed.”

In his wordy social media message, Trump argued that the U.S. may one day need to use an airbase located in the Chagos Islands to “eradicate a potential attack” by Iran.

Defending the UK’s decision to press ahead, justice minister Alex Davies-Jones said the government was prioritising the UK’s national security over Trump’s foreign policy statements.

“It’s really important to note that during his first meeting with President Trump, the Prime Minister reiterated this deal, and President Trump backed it. He said that this lease was a strong lease,” the minister told Times Radio.

“Just two weeks ago, the President again backed this and said that it was the best deal available. And just this week, the US administration again reaffirmed their commitment to the deal.”

The latest turn of events came almost a month after Trump branded the Chagos Island deal an act of “great stupidity.”

The US President said the UK was not wise to hand over the Islands and suggested it was one of the reasons he wanted to take over Greenland.

He wrote: “Shockingly, our “brilliant” NATO Ally, the United Kingdom, is currently planning to give away the Island of Diego Garcia, the site of a vital U.S. Military Base, to Mauritius, and to do so FOR NO REASON WHATSOEVER”

So, what is the Chagos Islands agreement, and why are people opposed to it?

The Chagos Islands have a long and complicated history of colonial rule, particularly under British rule.

Britain first took control of the Chagos Islands in 1814, after gaining authority over the islands from the French.

In 1965, the UK split the Chagos Islands from Mauritius three years before they gained independence. As a result, the Chagos Islands then became part of the British Indian Ocean Territory.

In the decades that followed, all native people born on the Chagos Islands were forcibly expelled to the Seychelles or Mauritius to make way for UK and US military base activity.

Human rights campaigners, who have called for full reparations to generations affected by the forcible displacement of islanders, argued the deal does not go far enough to address the wrongs of the past.

The expulsions are regarded as a shameful part of Britain’s modern colonial history, and Chagossians have spent decades fighting to return to the islands.

The United Nations‘ highest court, the International Court of Justice, previously ruled that the UK’s administration of the territory was unlawful and must end.

A joint statement from the UK and Mauritius governments said the new deal will be subject to a treaty that will “address wrongs of the past and demonstrate the commitment of both parties to support the welfare of Chagossians”.

The Foreign Office said the agreement means the status of the base will be undisputed and legally secure.

The UK has a route that allows people of Chagossian descent to apply for British citizenship.

The chain of Indian Ocean islands is claimed by Mauritius but is actually more than 2,000km away from the African nation.

Chagos has seven atolls and around 60 islands; of these, Diego Garcia is by far the largest.

Mauritius is an island off the east coast of Madagascar, also an island, which is off the coast of south-east Africa.

Chagos archipelago is a strategic point in the Indian Ocean between Africa and India, which is why it is a useful spot for nations seeking regional influence.

Around 3,000 people live on the islands, who are mostly British and American servicemen.

In May 2025, Starmer signed a deal ceding sovereignty over the Chagos Islands to Mauritius, which had been administered alongside the archipelago until 1965.

As part of the deal to hand back sovereignty, the UK and the US would be allowed to continue military activity through an army base on one of the islands for a multi-billion-pound fee.

The deal has already faced countless delays as leadership changed in both Mauritius and the US, amid pushback from various players and concerns that it would give China greater control over the region.

Despite initial challenges and recent legal challenges, the final agreement has now been reached.

The deal was halted in the days before the agreement was finally struck, following action by Chagossians Bernadette Dugasse and Bertrice Pompe.

Their case essentially argued against the UK government handing over sovereignty to Mauritius. Many people native to the Chagos Islands were expelled in the Sixties and Seventies by the US and UK governments as they established an airbase on Diego Garcia.

Central to the women’s argument are concerns about Mauritius’s treatment of the Chagossian people, and fears they may face challenges returning to the island, as they don’t hold citizenship in Mauritius.

“Chagossians were removed from their place of birth, without their consultation, and have been treated badly for 60 years. Since then we have been struggling to understand why we have been treated so poorly by the British government,” said Ms Pompe.

“Our human rights have been stripped away. Today the British government is repeating the same mistakes which it made 60 years ago.”

She added: “All our suffering and cries to be heard have been falling on deaf ears… I want to stay British and I also want the right to return to the Chagos Islands.”

A lawyer for Ms Pompe and Ms Dugasse said: “The Government’s attempt to give away the Chagossians’ homeland whilst failing to hold a formal consultation with the Chagossian people is a continuation of their terrible treatment by the authorities in the past.”

Bertrice Pompe and Bernadette Dugasse were born on the Chagossian island of Diego Garcia and are also British citizens.

They are two women who challenged the deal, arguing that it goes against their rights and may hinder their chances of returning to the Chagos Islands.

Labour’s political opponents have raised concerns that the agreement will allow China to gain influence in the area.

Former foreign secretary James Cleverly described the move as “weak, weak, weak” while former security minister Tom Tugendhat suggested it risked allowing China to gain a military foothold in the Indian Ocean.

He said United States officials have been “intimately involved” in the negotiations, telling Times Radio: “Every single sentence and paragraph has been through an inter-agency process, all of the agencies in Washington. We’ve secured all of their red lines in that negotiation.

“When you come to see the detailed treaty, which is really quite long with the exchanges of letters, you’ll see that this idea of a Chinese base is just hooey. It can’t happen, won’t happen.”

After the UK agreed to return the Chagos Islands last year, the Argentine foreign minister, Diana Mondino, said it was time to take steps to return the Malvinas (as the Argentinians call the islands).

“We welcome this step in the right direction and the end to outdated practices,” she said.

“Following the path we have already taken, with concrete actions and not empty rhetoric, we will recover full sovereignty over our Malvinas Islands.

“The Malvinas were, are and will always be Argentine.”

Argentina has long wanted back the Falklands but residents of the islands voted 99 per cent in favour of remaining part of the UK in 2013.

In a statement issued last year, Falklands governor Alison Blake sought to reassure residents that Britain’s commitment to the South Atlantic territory was “unwavering”.

She said the historical context of the two territories was “very different”.