Sam Francis and Kate Whannel

Political reporters

Reuters

Diego Garcia, the largest island in the archipelago, was separated from Mauritius along with the rest of the Chagos Islands in 1965 and now houses a US military base

Sir Keir Starmer has signed a deal to hand the Chagos Islands to Mauritius and lease back a key military base for £101m a year.

Under the terms of the deal Mauritius would gain sovereignty of the islands from the UK, but allow the US and UK to continue operating a military base on Diego Garcia for an initial period of 99 years.

After overcoming a last-minute legal challenge, the prime minister signed the deal in a virtual ceremony on Thursday.

Speaking at a press conference after the signing, Sir Keir said the deal was the “only way to maintain the base in the long term” and had secured “strong protections from malign influences” for the UK.

Sir Keir said the UK had to “act now” or face Mauritian legal action that could interfere with the Diego Garcia base.

The UK’s base in the Chagos Islands is “one of the most significant contributions that we make to our security relationship with the United States”, he added.

Speaking from the UK’s military headquarters Sir Keir said: “Almost everything we do from the base is in partnership with the US.

“President Trump has welcomed the deal along with other allies, because they see the strategic importance of this base and that we cannot cede the ground to others who would seek to do us harm.”

Defence Secretary John Healey is due to make a statement in Parliament on the future of the military base later.

The deal has attracted strong criticism from opposition politicians in the UK, who have questioned the cost and say an important military base should not be given to a country with close links to China.

Speaking ahead of the deal being signed, Conservative leader Kemi Badenoch said it was an example of “Labour chaos”.

“We should not be paying to surrender British territory to Mauritius,” she said.

“The fact that Labour is negotiating something that sees the British taxpayer in hoc for potential billions is completely wrong.”

Reform UK deputy leader Richard Tice joined a group of Chagossians protesting outside the High Court earlier, saying he wanted to see “another Starmer surrender sell out” stopped.

Getty Images

Members of the Chagossian community held a protest outside the High Court as a legal challenge was dismissed

It comes after the High Court dismissed a legal challenge, which temporarily blocked the deal when a last-minute court injunction was granted at 02:25.

The legal action was brought by two Chagossian women, Bernadette Dugasse and Bertrice Pompe, who were both born on Diego Garcia, the largest of the islands, and would like to be able to return.

In October, the two countries said that under the deal Mauritius would be “free to implement a programme of resettlement” on the islands, excluding Diego Garcia, which is home to the UK-US military base.

In a pre-action letter, lawyers for the two women said the Chagossian people had unlawfully not been given a say in the future of the islands, despite being the native inhabitants.

They also said that they did not trust Mauritius to treat the Chagossians fairly, and that they would face “severe obstacles” as British citizens who do not hold Mauritian nationality, including possible racial discrimination and the loss of the possibility of returning.

In a witness statement to the High Court, senior Foreign Office official Harriet Matthews said the delay had “caused harm to the UK’s reputation” with Mauritius and the US.

Following the court’s decision, Ms Pompe said it was “a very very sad day” but added: “We are not giving up.”

“We don’t want to give our rights, hand over our rights to Mauritius. We’re not Mauritians,” she said.

On Thursday, representatives of the Chagossian community met Foreign Office Secretary David Lammy and minister Stephen Doughty, for discussions on the sovereignty of the territory.

In a call immediately after the meeting, Jemmy Simon, from the Chagossian Voices group, told the BBC there was “nothing in there [the deal] that is any good for us”.

“I’m beyond horrified and angry right now.”

She said the deal would include a £40m support package, which the Mauritian government could use to help resettlement.

“They [the British government] promised to look out for our best interests – absolute rubbish,” she said.

“It is up to Mauritius to decide if we will get to resettle on the outer islands or not, but they don’t have to if they don’t want to.”

PA

Bertice Pompe (left) and Bernadette Dugasse (right) outside the High Court in central London on Thursday

The Chagos Archipelago was separated from Mauritius in 1965, when Mauritius was still a British colony.

Britain purchased the islands for £3m, but Mauritius has argued it was illegally forced to give away the islands in order to get independence from Britain.

In the late 1960s Britain invited the US to build a military base on Diego Garcia and removed thousands of people from their homes on the island.

An immigration order, issued in 1971, prevented the islanders from returning.

The Chagos islanders themselves – some in Mauritius and the Seychelles, but others living in Crawley in Sussex – do not speak with one voice on the fate of their homeland.

Some are determined to return to live on the isolated islands, some are more focused on their rights and status in the UK, while others argue that the archipelago’s status should not be resolved by outsiders.

In recent years, the UK has come under growing international pressure to return the islands to Mauritius, with both the United Nations’ top court and general assembly siding with Mauritius over sovereignty claims.

In late 2022, the previous Conservative government began negotiations over control of the territory but did not reach an agreement by the time it lost power in the 2024 general election.