Mauritius vs UK: The hidden story of Chagos Islands

It is now clear that the tiny island of Diego Garcia was central in US President Donald Trump’s grand scheme as he contemplated war with Iran.

He expressed displeasure at the UK's refusal to allow America use of the island, saying: “UK has been very uncooperative with that stupid island that they have.”

Diego Garcia is a small, isolated island in the Chagos Archipelago at the heart of the Indian Ocean. But it is home to what analysts describe as one of the “most important” military bases for America.

“In fact, it is described as the most important base outside America itself,” lawyer Bashir Ebrahim Khan tells TRT Afrika, adding: “Remember that America has something like 1,000 bases around the world, but none of them is as important as the one on Diego Garcia.”

When it comes to military partnerships, “you cannot find any better or bigger partnership than the UK-US deal on Diego Garcia.”

Trump had envisaged a war against Iran with Diego Garcia in mind. When it was ruled out, he didn’t conceal his disappointment.

“It’s taken three, four days for us to work out where we can land. It would have been much more convenient to land there rather than flying so many extra hours,” Trump said during a White House press conference on March 3.

The making of Diego Garcia base

Diego Garcia, is the biggest island in the Chagos Archipelago, covering nearly 6,720 acres of land. The American military installations website calls it the “Footprint of Freedom" for its shape, regional location, and strategic importance, noting it sits very close to the geographic center of the Indian Ocean.  

“If you look at the shape of Diego Garcia, it looks a bit like a horseshoe, so you can enter a very vast area of the sea, which is very, very useful militarily speaking because all their military ships can go in, and all they have to do is protect the mouth of the horseshoe,” Khan, explains.

With nearly 2,000 kilometres separating the island from Mauritius, from where it was colonially administered from, Chagos was the perfect site for a secret outpost.

The Americans and the British sealed a deal in 1966 to set up a joint military base on the island, but analysts say the base was built on a history of colonial misadventures and secrecy.

Diego Garcia was the spot where the interests of the two NATO allies aligned, a realisation prompted by China’s 1962 attack on India.

This coincided with Yemen's independence demands. The Gulf of Aden was home to a key military base that the coloniser used to control the Middle East. Yemen's demand for the British to leave Aden was a blow.

Peter Thorneycroft, the then-UK defense secretary, travelled to Washington to meet his US counterpart Robert McNamara, who was equally unsettled with the developments in Asia, amid Cold War tensions.

According to Khan, who has sifted through correspondence leading up to the UK-US deal, McNamara said to Thorneycroft: “If China or the Soviet Union were to launch attacks in some other countries, we Americans have nothing in the Indian Ocean; from the west of the Indian Ocean all the way to the Pacific. We don't have a base. So I think you British and us Americans should start thinking about how we can develop a base together.”

It was precisely what Thorneycroft was hoping for. The message sparked excitement among his colleagues in government back in London.

They exclaimed, “Oh my God, this is a gift from God,” Khan narrates, noting that Britain was fairly poor at the time and couldn’t afford to develop another base elsewhere.

“So they said we need to grab that offer from America, because we will solve a lot of our own problems. We will replace Aden and, at the same time, get a joint military base with the biggest military power.”

US-UK military pact

By then, the US had already surveyed the Indian Ocean and Diego Garcia Island in Chagos was top of their list. Being a colonial territory of the UK since 1814, the Americans struck a deal. The US would fund the project while the UK would provide the land.

 But there was one condition. The Americans wanted the island “sanitized,” Khan says. “Sanitized in their military jargon means void — the absence of any human presence.”

The British undertook to fulfil their end of the bargain, which meant uprooting the Chagosians from their birthplace, to make way for the military project.

However, Mauritius had already filed for independence, complicating the British plans. The United Nations Charter, adopted in 1960, prohibited the dismemberment of territories seeking independence.

Still the two NATO allies were undeterred.

“While Mauritius was following the roadmap with the colonial office towards its own independence, Britain and America were also following a secret roadmap to secure Diego Garcia — in my view, illegally,” Khan says.

While independence negotiations were going on, the colonial secretary then, Anthony Greenwood called aside four political officials from Mauritius to inform them of a plan to set up an American communications base on Diego Garcia.

After failing to get a favourable answer from the politicians, Harold Wilson, then British Prime Minister, convened a meeting with the Mauritian Prime Minister appointed by the colonial office.

“Wilson said to the Premier of Mauritius: ‘You see, if you make life difficult, you don't want to consent. I can do it without your permission. We can have something called order in council.”

Approved by the monarch in person, the Order in Council was a legal tool used by the colonizer to introduce some legislations without going through parliament.

On November 8, 1965, the British detached the islands from Mauritius by Order in Council and Chagos became formally established as the British Indian Ocean Territory.

The following year, on December 30, 1966, the UK-US agreement on the joint military base came into force and the evacuation of the roughly 3,000 Chagosians then began, discreetely at first.

“At that time, even before 1965, all the way to 1970, it was still a secret military project between Pentagon, Ministry of Defense in UK and State Department,” Khan notes.

“That's why throughout that time, they kept saying to each other and to inform all their embassies around the world, please never, if you are asked questions by outsiders, journalists or other foreign countries about the possibility of us setting up a base in the Indian Ocean, pretend you don't know anything, you've never heard of this. Never mention the base.”

Secrecy was vital to avert trouble first with the UN and secondly, with US Congress, which was yet to approve funding for the project.

Chagosian leader Olivier Bancoult was only 4 years old when his family was forced out of the Island. He still remembers how it all happened.

“It was very sad,” he tells TRT Afrika, recalling how his mother was deceived to take his sister who had been hurt by a wheel cart to Mauritius for better treatment.

“We all moved to Mauritius in a view to return because we left all our belongings in Perhos Banos. Unfortunately, when we arrived in Mauritius, three months after, my sister passed away, and when my parents wanted to return, this is when we knew that it will be impossible for us to return because the island has been given to America to build a US military base.”

Legal battles

As Olivier Bancoult grew up, the injustice against his people became clear, spurring him to pursue justice immediately after high school.

“This is the reason why I've been involved in the struggle. I took legal action against the UK government,” he says.

“I started the legal procedure in 1997 and I won my first landmark victory on November 3, 2000. It was a strong judgment in our favor, we were recognized as the natives of the island.”

But nothing happened despite the ruling. The Mauritian government took the battle to the UN’s International Court of Justice (ICJ), arguing that its decolonization was not complete following Chagos’s detachment.

Khan, who was present when the ICJ rendered its advisory opinion in February 2019, recalls the words of the president of the court.

“He said what do you mean they consented? In 1965 Mauritius was not a sovereign country, so all these people whom you are calling the prime minister, or the attorney general, or some other ministers — these were ‘fancy’ titles given to them for the pleasure of Her Majesty. They had no legal meaning internationally.”

The court pointed out that Britain had violated the UN Charter forbidding against the dismantling of a territory before its independence.

ICJ ordered the coloniser to pack up and leave Chagos by August 2019, but Britain declined, arguing that the decision was only “an advisory opinion.”

By then, the 1966 UK-US pact, initially set for 50 years, had expired in 2016, with a new extension approved until 2036.

Sovereignty deal

After years of legal battles, UN resolutions, and an ICJ opinion against UK control, the British negotiated a deal to transfer sovereignty to Mauritius, while keeping a 99-year lease for the Diego Garcia base.

The Mauritian government embraced the prospect of an average $136 million annual lease payment, culminating in a UK-Mauritius sovereignty deal signed in May 2025.

Both the Biden and Trump administrations endorsed it, and the bill only needed ratification by the UK parliament.

However, in January 2026, President Trump had a change of mind and lambasted the deal, describing it as an “act of total weakness” and “great stupidity” by a NATO ally.

In the UK, opposition to the deal is also mounting, and Prime Minister Kier Starmer, has had to temporarily withdraw the bill from the house.

“Let me remind the Prime minister, he is giving away our territory, and we have to pay 35 billion pounds for the privilege,” Opposition Leader Kemi Badenoch said.

Some echo Trump's sentiments about foreign threats, suggesting the islands could fall to China or Russia, but it’s quite the opposite according to Stammer. A lease on Diego Garcia would ensure no other foreign power establishes a base on the islands.

However, Trump remains adamant, concluding his 18th February post with a warning: “DO NOT GIVE AWAY DIEGO GARCIA.”

Whether the sovereignty deal is a step in the right direction is also a bone of contention even among Mauritians and Chagosians.

“You either have sovereignty or you don't, but you cannot have sovereignty over only a small part of the territory,” Khan offers.

However, Bancoult says it is best to take the deal. He is concerned the native Chagosians are diminishing. The youngest is 53, and the oldest is 100 years old. “Day-by-day, our people are disappearing,” he says and wonders: “How long should we go?”

"My mother passed away in September 2024, and one of her last wishes was to see her island one last time, but this didn’t happen," Frankie Bontemps says, fighting back tears, adding: “I feel like the natives of the island will never see their birthplace."

If the sovereignty deal goes through, then the UK hands over Chagos but retains Diego Garcia on a 99-year lease, with possibility of extension. Otherwise, the existing UK-US agreement remains until 2036 and might also be extended further.

So whether or not the colonial ruler surrenders sovereignty over Chagos, the islands’ freedom still remains a distant dream.