FACTBOX: Key facts about Chagos Islands deal signed by UK and Mauritius

U.S. President Donald Trump has called Britain's deal to cede sovereignty of the island of Diego Garcia in the Chagos Islands to Mauritius an "act of total weakness", putting the agreement back into the spotlight eight months after it was signed.

Britain signed the multi-billion dollar deal after a last-gasp injunction was overturned, which secured it a lease for the strategically important UK-U.S. air base on Diego Garcia over the next century.

Here are some key points about the islands and the contentious deal:

ISLANDERS DISPLACED

The Chagos Archipelago is a group of six atolls with more than 600 islands in the Indian Ocean, 500 km (300 miles) south of the Maldives and halfway between Africa and Indonesia.

Around 4,000 people are currently stationed on the islands.

No indigenous inhabitants, often referred to as Chagossians or Ilois, have lived there since Britain forcibly displaced up to 2,000 people, mostly former agricultural workers, from the islands in the late 1960s and early 1970s to establish the Diego Garcia base.

THE DEAL

Under increasing international pressure, Britain agreed in October 2024 to transfer sovereignty of the Chagos Islands to Mauritius, a former colony that gained independence in 1968. The deal, however, drew criticism from lawmakers as well as Britons born on Diego Garcia.

In May 2025, Britain said it would pay Mauritius 101 million pounds ($136 million) per year - calculated to be worth 3.4 billion pounds over the lifetime of the deal - to secure the future of the Diego Garcia military base under a 99-year lease.

At the time, the U.S. said it "welcomed the historic agreement", commending both countries' leaders for their vision. In February 2025, ahead of the signing, Trump also expressed preliminary support for the deal.

Canada, Australia, New Zealand and India have also backed the agreement.

SIGNIFICANCE

Diego Garcia serves as a key military base in the Indian Ocean for the U.S. and Britain.

Recent operations launched from Diego Garcia include bombing strikes against Houthi targets in Yemen in 2024 and 2025, humanitarian aid deployments to Gaza and attacks against Taliban and al Qaeda targets in Afghanistan in 2001.

China also has a growing reach in the region, including close trade ties with Mauritius.

UN COURT'S VIEW

Britain split the archipelago off from its colonial island territory of Mauritius in 1965, three years before granting independence to Mauritius - minus the islands.

In 2019 after a request by the United Nations General Assembly, the International Court of Justice issued a non-binding ruling calling on Britain to give up control, saying it wrongfully forced the population to leave to make way for the base.

CONCERNS

U.S. Secretary of State Marco Rubio raised concerns in February 2025 about potential threats to U.S. security, particularly in light of China's influence in the region.

Mauritian Prime Minister Navin Ramgoolam, who was elected after the initial agreement was reached, also questioned the deal when he took office. Ramgoolam had wanted Trump to look at the plan and say whether it was a good arrangement.

Some Chagossians, many of whom ended up living in Britain after being removed from the archipelago, have protested against the agreement on the grounds that they were not consulted.

Kemi Badenoch, leader of the opposition in Britain, said on Tuesday on X that the deal was "complete self sabotage" that made "us and our NATO allies weaker".

LEGAL CHALLENGE

Before the deal was signed, a UK High Court judge issued a last-minute injunction sought by Bernadette Dugasse and Bertrice Pompe, British nationals who were born in Diego Garcia and criticised the deal for excluding Chagossians.

The injunction was overturned hours later by Britain's High Court, clearing the way for the deal to be signed.

($1 = 0.7446 pounds)

-Sam Tabahriti and Paul Sandle/Reuters