In the vast expanse of the Indian Ocean lies the Chagos Archipelago, a remote cluster of islands that has evolved into a major fault line in global diplomacy. Once a symbol of Cold War strategy and colonial authority, the islands, particularly Diego Garcia, now sit at the intersection of decolonization, military necessity, and shifting great power politics.
Home to one of the world’s most strategically important U.S.-UK military bases, Chagos has become a test case for international law, alliance cohesion, and historical accountability.
This article traces the archipelago’s political evolution from its controversial separation from Mauritius to the latest diplomatic rupture between Washington and London.
A Colonial Carve-Up
Separation from Mauritius and Forced Expulsion
The modern Chagos dispute begins in 1965, when the United Kingdom detached the Chagos Archipelago from Mauritius, then a British colony, creating the British Indian Ocean Territory (BIOT).
The move was driven by Cold War geopolitics. Britain and the United States sought a secure military outpost in the Indian Ocean, beyond the reach of regional instability.
To make way for the base on Diego Garcia, the UK forcibly expelled the islands’ entire native population between the late 1960s and early 1970s. Around 1,500 Chagossians were removed from their homeland and resettled in Mauritius and the Seychelles.
British officials later acknowledged the episode as a “shameful chapter” in the country’s colonial history.
To this day, Chagossian communities continue to campaign for the right to return, reparations, and recognition of their displacement.
Diego Garcia
The Strategic Heart of the Indian Ocean
Despite the human cost, Diego Garcia rapidly became a cornerstone of Western military power.
The base has supported operations during:
- The Gulf War
- The Afghanistan conflict
- Recent air and naval strikes against Houthi targets in Yemen
Its strategic location allows rapid deployment of long-range bombers, surveillance aircraft, and logistics assets, making it central to U.S. and UK efforts to counter threats from China and Russia across the Indo-Pacific.
A senior Western defense official once described Diego Garcia as “irreplaceable real estate in modern warfare.”
International Law Pushes Back
Courts, Resolutions, and Rising Pressure
British sovereignty over Chagos began to unravel under international scrutiny in the 21st century.
In 2019, the International Court of Justice issued a landmark advisory opinion declaring that the separation of Chagos from Mauritius was unlawful and that the UK must end its administration “as rapidly as possible.”
Later that year, the UN General Assembly overwhelmingly backed Mauritius, with only six countries voting against the resolution.
Legal momentum continued in 2021, when the International Tribunal for the Law of the Sea rejected the UK’s maritime claims around Chagos, reinforcing Mauritius’s sovereignty argument.
Though advisory and not directly enforceable, these rulings created intense diplomatic pressure. Formal negotiations between the UK and Mauritius began in 2022 under a Conservative government.
Human rights organizations argued that Chagossians were being excluded once again from decisions affecting their future.
The 2025 Sovereignty Agreement
A Deal That Tried to Satisfy Everyone
A breakthrough came in October 2024, followed by the formal signing of a treaty on May 22, 2025, between UK Prime Minister Keir Starmer and Mauritian Prime Minister Navin Ramgoolam.
Under the agreement:
- Mauritius gains sovereignty over the entire Chagos Archipelago, including Diego Garcia
- The UK retains operational control of the military base through a 99-year lease, renewable for 40 more years
- Britain will pay Mauritius approximately £101 million annually, totaling around £3.4 billion
- Additional funding supports Chagossian welfare and limited resettlement on outer islands, excluding Diego Garcia
Starmer defended the deal as unavoidable.
“This agreement is vital to secure the base’s future in the face of mounting legal threats,” he said.
The United States initially endorsed the arrangement. Then-Secretary of State Marco Rubio called it “a monumental achievement” that preserved shared security interests.
Backlash at Home and Abroad
Chagossians and Critics Push Back
The agreement immediately faced opposition.
Chagossian exiles launched a High Court challenge, arguing they were never consulted and feared discrimination under Mauritian governance. The challenge failed, but anger remains.
UN human rights experts criticized the deal for falling short on the right of return, compensation, and meaningful self-determination.
“It resolves sovereignty between states,” one UN expert noted, “but not justice for the people who were removed.”
Trump’s 2026 Reversal
From Support to Scathing Condemnation
The deal’s stability collapsed in January 2026, when U.S. President Donald Trump abruptly reversed his administration’s position.
In a January 20 Truth Social post, Trump denounced the agreement as:
“An act of GREAT STUPIDITY and total weakness.”
He accused the UK of surrendering strategic territory “for no reason whatsoever” and linked the issue to his renewed push to acquire Greenland, arguing that America must directly control key global locations to counter China and Russia.
The reversal stunned diplomats. Only months earlier, Trump’s administration had backed the deal as essential to maintaining Diego Garcia.
UK opposition figures seized on Trump’s remarks. Nigel Farage called the intervention a de facto American veto.
On X, users warned of Chinese influence, questioning Britain’s strategic judgment and pointing to recent approvals for Chinese-linked projects in London.
Mauritius Responds
“Sovereignty Is No Longer Debatable”
Mauritius rejected Trump’s criticism outright.
The country’s attorney general stated:
“The sovereignty of the Chagos Archipelago should no longer be subject to debate under international law.”
Chagossian leaders, meanwhile, appealed directly to Trump, urging him to block any Chinese presence in the islands and offering symbolic assurances to preserve the U.S.-UK base.
Where Things Stand
Tensions, Alliances, and an Uncertain Future
As of January 21, 2026, the UK government continues to defend the agreement, insisting it secures the base for generations and includes safeguards against hostile powers.
The treaty awaits full ratification in the UK Parliament, where scrutiny has intensified following Trump’s remarks.
Diplomatic tensions between Washington and London have sharpened, straining alliance unity and reopening debates over post-imperial responsibility versus strategic realism.
Analysts note broader regional implications. India has strengthened ties with Mauritius, expanding its Indian Ocean influence, while Washington remains wary of China’s growing footprint.
Critics warn of potential A2/AD vulnerabilities. Supporters argue the deal represents overdue ethical decolonization.
Human Rights Watch summed up the dilemma:
“Trump’s attack ignores decades of Chagossian suffering, reducing a question of justice to a matter of military convenience.”
A Test Case for a Multipolar World
The future of the Chagos Archipelago remains unresolved. Its fate now sits at the crossroads of historical redress, security imperatives, and great power rivalry.
As arguments rage across diplomatic channels and social media alike, Chagos has become more than a group of islands. It is a measure of how international law, alliances, and morality will coexist in an increasingly multipolar world.