Where are the Chagos Islands, what is the deal between UK and Mauritius, and why it is a positive move for India: Explained

On 22nd May, British Prime Minister Keir Starmer finalized an agreement to transfer the Chagos Islands to Mauritius while leasing a crucial military base for £101 million annually. The deal outlined that Mauritius would regain sovereignty of the islands but the United States and the United Kingdom would be permitted to maintain a military facility on one of the islands, Diego Garcia, for a first 99-year period.

Starmer stated that the agreement enhanced the United Kingdom’s national security and was the only feasible solution to ensure the base’s long-term viability. The development transpired after a high court verdict that enabled the formal signing of the contentious agreement. Following their surrender by France in 1814, the islands have been governed by the United Kingdom.

Decades of British rule over the Indian Ocean archipelago which has been the focus of continuous legal and diplomatic conflicts since the islands broke away from Mauritius in 1965 will come to an end with this accord. The multibillion-pound decision withstood months of criticism on both sides of the Atlantic and an impromptu judicial challenge.

“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,” Starmer conveyed from UK’s Northwood military headquarters. “If we did not agree this deal the legal situation would mean that we would not be able to prevent China or any other nation setting up their own bases on the outer islands or carrying out joint exercises near our base. No responsible government could let that happen,” he declared.

Britain set to pay billions to Mauritius

The contract will amount to £3.4 billion ($4.5 billion) for Britain throughout the duration of the lease as the country shut down its last colonial outpost on the continent while still exercising control over the crucial military base. Diego Garcia, the largest of the islands in the chain accommodates a strategically critical American naval and bomber base.

According to the prime minister, the United States-run base is situated “right at the foundation of our safety and security at home.” He pointed out that it is essential for British intelligence and counterterrorism efforts. He highlighted that the “full assessment” of the motivations behind the settlement was “highly classified” while speaking in Hertfordshire.

However, he mentioned that the country was at risk of a expected legal defeat in international courts if a settlement had not been reached. He added that such failure would have resulted in huge punitive damages. The United Nations-backed International Court of Justice’s 2019 advisory judgment which urged the United Kingdom to return the islands and end its colonial administration, sparked the transfer of sovereignty.

The government’s intention to sign the deal with Mauritius was put on hold on 22nd May when a United Kingdom High Court judge granted a last-minute injunction on the request of British citizens Bernadette Dugasse and Bertrice Pompe who were born in Diego Garcia. The contract had been criticized by them for not including Chagossians. The contract could be finalized once the British High Court reversed the injunction a few hours later.

An initial deal between the two nations was struck in October. Nevertheless, it was halted when Britain indicated that it needed to wait for US President Donald Trump’s assent. A change of government in Mauritius also caused the transaction to stall along with disputes arising about the amount that the United Kingdom should pay for Diego Garcia’s lease. Britain receives an undisclosed payment from the United States to run the base.

What are the Chagos Islands: A brief history

Located around 500 kilometres (310 miles) south of the Maldives archipelago, the Chagos Archipelago is a collection of seven atolls made up of 58 separate tropical islands in the Indian Ocean. There are about 4,000 personnel stationed on the islands. There haven’t been any indigenous inhabitants, often referred to as Chagossians or Ilois, since Britain forcibly uprooted up to 2,000 people, mostly former agricultural labourers, from the islands in the late 1960s and early 1970s to build the Diego Garcia base.

• 1783: Slaves from Africa were the first people to settle in the Chagos Islands. They were employed on farms that produced coconuts and copra which the French created. The arrival of indentured Indians followed their emancipation.
• 1814: The Chagos Islands and neighboring Mauritius were officially taken from France by Britain after Napoleon’s abdication and exile during the Napoleonic Wars.
• 1965: As Mauritius and the UK negotiate independence, the Chagos Islands became the British Indian Ocean Territory (BIOT). The UK and the US also agreed to establish a military base on one of the islands, Diego Garcia.
• 1968: The United Kingdom retained control of the BIOT while Mauritius was granted independence. The latter challenged that it was unlawfully compelled to hand over the islands to gain independence from Britain in exchange for £3 million.
• 1967-1973: All residents of the Chagos Islands were compelled to relocate with the majority moving thousands of kilometers away to the main island of Mauritius or the Seychelles and even accept invitations to stay in England, primarily in Crawley in West Sussex to make room for a UK-US military installation. According to Human Rights Watch, the forced relocation constituted an offense against humanity and an “appalling colonial crime.”
• 1982: The United Kingdom consented to contribute £4 million to a trust fund founded for the Chagossians under a Mauritian law.
• 2000: The removal of the Chagossians was deemed illegal by United Kingdom’s High Court.
• 2008: After a number of lower British court judges ruled that the exile of Chagossians was illegal, the UK’s highest court at the time, the House of Lords, rules against their right of return.
• 2010: A UK Foreign Office official told the US that a decision to set up a “marine protected area” (MPA) would “put paid to resettlement claims of the archipelago’s former residents,” according to a May 2009 US diplomatic cable made public by WikiLeaks.
• 2015: According to a United Nations tribunal, Britain violated the law when it constructed a marine protected area (MPA) in the Chagos Islands. It denied Mauritius its fishing rights as well as failed to consult the island nation.
• 2016: The UK government continued to forbid Chagossians from returning home after announcing a £40 million support package to help and compensate them.
• 2019: The UN’s highest court, the International Court of Justice issued an advisory opinion declaring that the United Kingdom must return the isolated Indian Ocean archipelago to Mauritius “as rapidly as possible” and pronounced that the ongoing British control of the area was unlawful. The motion denouncing Britain’s control of the islands was overwhelmingly supported by the UN general assembly. However, the UK did not abide by the motion which allotted it six months to leave and reunify the islands with Mauritius.
• 2021: The prime minister of Mauritius called on the UK to stop its “illegal occupation” of the Chagos Islands as the UN’s special international maritime court dismissed the latter’s claim to sovereignty over the islands. A fishing boat carrying Tamil asylum seekers was rescued and transported to Diego Garcia in the same year. They stayed there and characterized the conditions as horrible and akin to a prison. Self-harm and attempted suicides had been widely reported.
• 2022: The United Kingdom declared that it has consented to kick off talks with Mauritius over the future transfer of the Chagos Islands.
• 2024: After years of acrimonious conflict over Britain’s final African colony, the UK decided to cede the Chagos Islands to Mauritius and keep control of the military facility on Diego Garcia which it shares with the US.

The military station on Diego Garcia, which has aided US military operations from the Vietnam War to wars in Iraq and Afghanistan, is arguably the most well-known feature of the archipelago. The United States admitted in 2008 that the station had also been utilized for covert rendition flights involving suspected terrorists.

The US has designated the station, which has approximately 2,500 primarily American employees, “an almost indispensable platform” for security operations in the East Africa, South Asia and the Middle East.” During a recent campaign of heavy airstrikes against Yemen’s Houthi rebels in 2024 and 2025, the United States sent a number of B-2 Spirit bombers equipped with nuclear weapons to Diego Garcia. It has also been the site of launching attacks against Taliban and al-Qaeda targets in Afghanistan in 2001 along with humanitarian aid deployments to Gaza.

What was the delay

After Starmer’s Labour Party was elected in July, negotiations to transfer the islands to Mauritius resumed which were originally commenced in 2022 under the previous Conservative government in the United Kingdom. The British government declared in October that it was completing the terms of a treaty that would transfer sovereignty of the islands to Mauritius with Diego Garcia remaining under British rule.

Former President Joe Biden of the United States praised the accord as a “historic agreement” that guaranteed the Diego Garcia base’s survival. The government’s decision to cede sovereignty of the region, however, was criticized by Britain’s opposition Conservatives, who charged that it put the country and its allies at risk. Marco Rubio, who is currently Secretary of State, stated last year that it was “a serious threat” to the national security of the United States.

India supports the agreement

India expressed that it has always backed the “legitimate claim” of Mauritius over the Chagos Archipelago in accordance with its core stance on “decolonization, respect for sovereignty, and the territorial integrity of nations” and applauded the UK’s decision to yield the sovereignty of the Chagos Islands to Mauritius.

“The formal resolution of the longstanding Chagos dispute through this bilateral treaty is a milestone achievement and a positive development for the region. This is further to the understanding between the two sides reached in October 2024, and marks the culmination of the process of decolonisation of Mauritius in the spirit of international law and rules-based order,” the Ministry of External Affairs in New Delhi mentioned in a statement.

Furthermore, the MEA asserted, “As a steadfast and longstanding partner of Mauritius, India remains committed to working closely with Mauritius and other like-minded countries to strengthen maritime security and regional stability and ensure peace and prosperity in the Indian Ocean region.”

“India played a quiet but important role in the background. It firmly backed the principled Mauritian position, supporting its stance on the need to do away with the last vestiges of colonisation. At the same time, it consistently encouraged both sides to negotiate with an open mind and with a view to achieving mutually beneficial outcomes,” according to ANI.

They added, “It is believed that the final outcome is a win for all sides involved and will reinforce long term security in the Indian Ocean region.”

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