Diego Garcia & Chagos Islands Deal: Interactive Breakdown
Diego Garcia and the Chagos Islands: A Strategic Shift
The UK and Mauritius agreement to transfer sovereignty while maintaining a critical military base reshapes geopolitics in the Indian Ocean
On 22 May 2025, the UK and Mauritius signed a historic agreement transferring sovereignty of the Chagos Archipelago to Mauritius, addressing decades of legal disputes. The deal allows the UK to secure a 99-year lease on Diego Garcia, the largest island in the archipelago and home to a strategically critical joint UK-US military base.
The Chagos Islands became a focal point of controversy when Britain separated them from Mauritius in 1965 to create the British Indian Ocean Territory. This separation came just three years before Mauritius gained independence, and the move was heavily contested. Between 1968 and 1973, approximately 2,000 inhabitants—the Chagossian people—were forcibly removed to accommodate the military base. Their displacement raised persistent human rights questions that shaped international relations for more than 50 years.
Where Diego Garcia Sits: Geography and Strategic Position
Understanding why this remote atoll matters to global security
Strategic Location
Diego Garcia sits approximately 1,116 miles southwest of India and 2,197 miles east of Tanzania, roughly halfway between East Africa and Southeast Asia. At roughly 7 degrees south of the equator, the atoll is located near the geographic center of the Indian Ocean. Its position enables rapid power projection capabilities toward the Middle East, South Asia, and Southeast Asia—regions of significant strategic interest.
The island’s physical characteristics make it uniquely suitable for military operations. It features a natural deep-water lagoon, a 12,000-foot runway capable of accommodating the heaviest US aircraft—including B-2 and B-52 bombers—and extensive naval facilities. The base serves as a logistical hub for power projection across three continents.
According to the official UK-Mauritius agreement, the base houses advanced satellite communication systems used by the UK and US to monitor and secure communications across the region. The location provides unrestricted access to the electromagnetic spectrum, enabling monitoring of hostile activity from foreign states.
Key Events: From Separation to Settlement
How a colonial decision in 1965 led to a 2025 agreement
1965
Britain separates the Chagos Islands from Mauritius, creating the British Indian Ocean Territory. The UK purchases the archipelago for £3 million compensation to Mauritius.
1968–1973
Approximately 2,000 Chagossian inhabitants are forcibly removed to make way for the Diego Garcia military base. Most relocate to Mauritius, the UK, and the Seychelles.
1973
Naval Support Facility Diego Garcia becomes operational, serving as a joint UK-US military installation.
1980s–1990s
Diego Garcia serves as a launch point for B-52 bombers conducting extended missions during the 1991 Gulf War, alongside bomber operations from bases in Saudi Arabia, the United Kingdom, and Spain.
2019
The International Court of Justice issues a non-binding advisory opinion stating the UK’s administration of the Chagos Islands was unlawful and that sovereignty should be returned to Mauritius.
October 2024
The UK and Mauritius reach initial agreement on the transfer of sovereignty after nearly two years of negotiations involving 13 rounds of talks.
22 May 2025
Prime Ministers formally sign the sovereignty agreement. The UK commits to a 99-year lease with Mauritius on Diego Garcia, extendable by a further 40 years.
20 January 2026
President Trump publicly criticizes the agreement on Truth Social, calling it an “act of total weakness” and linking it to his bid to acquire Greenland.
The Deal Explained: What the UK and Mauritius Agreed To
Key terms of the historic sovereignty transfer
Annual Lease Payment
£101M
Per year for 99 years, indexed to inflation
Total NPV Cost
£3.4B
Net present value in 2025 prices
Lease Period
99+40
Years, with further extension options
Protection Zone
24 NM
Nautical mile buffer around Diego Garcia
What Changes and What Stays the Same
Sovereignty: Mauritius gains full sovereignty over the entire Chagos Archipelago. Military Operations: The UK retains full control of Diego Garcia and its operations remain unchanged. Access Rights: Both the US and UK retain unrestricted military access for 99 years. Buffer Zone: A 24-nautical-mile exclusion zone surrounds Diego Garcia where no construction or installations can proceed without UK approval. Foreign Military: Foreign security forces are explicitly prohibited from the outer islands.
Why This Cost Makes Sense
The UK government estimated the total cost at £3.4 billion over 99 years (roughly £101 million annually). While this figure generates political debate, context matters: relocating or rebuilding a comparable military base elsewhere would exceed £10–15 billion over decades. The annual lease represents less than 0.02% of the UK defense budget and costs significantly less than operating a single aircraft carrier without aircraft for one year.
Why the UK Government Pursued This Deal
International court rulings had created operational uncertainty. The UK government expressed concern that without an agreement, contractors might refuse to work at the base due to legal exposure, international aviation rules could be challenged, and rival powers could establish a presence on surrounding islands. According to UK government statements, the 2019 ICJ ruling and potential follow-up judgments threatened to render the base inoperable without a settlement with Mauritius.
Who Supports, Who Opposes: Key Stakeholder Positions
Different actors view the agreement through their own strategic interests
UK Government (Labour)
Prime Minister Keir Starmer
Describes Diego Garcia as “right at the foundation of our safety and security at home.” The UK government states the deal secures the base for generations with robust provisions keeping its unique capabilities intact.
Five Eyes Alliance
US, Canada, Australia, New Zealand
All major Western security partners publicly welcomed the agreement. The deal removes uncertainty threatening base operations and secures a critical strategic asset for decades.
India
Ministry of External Affairs
Welcomed the agreement as an important step in completing Mauritius’s decolonization in line with international law and a rules-based order.
Japan and South Korea
Regional Partners
Both nations have expressed support for the agreement, viewing the stable operation of Diego Garcia as beneficial to regional security and freedom of navigation in the Indian Ocean.
Mauritius (Current Government)
Prime Minister Navin Ramgoolam
Described the agreement as completing “the total process of decolonization” for the nation. Mauritius gains sovereignty and a substantial annual income supporting development projects.
President Donald Trump
US President (January 2026)
Posted on Truth Social that the transfer is an “act of total weakness” and “great stupidity.” Frames the agreement as evidence of UK military decline and links it to his Greenland acquisition goals.
UK Conservative Party
Opposition Leaders Kemi Badenoch & Nigel Farage
Both called the agreement a “surrender” and criticized the £3.4 billion cost. Conservative MPs tabled a motion of censure against the Labour government in Parliament.
Chagossian Community
Displaced Population & Descendants
Community views are divided. UK-based groups including Chagossian Voices oppose the agreement, citing exclusion from negotiations and arguing for full right of return to all islands including Diego Garcia. Chagossians in Mauritius, including Olivier Bancoult of the Chagos Refugees Group, welcomed the agreement as enabling resettlement opportunities. The UN expressed concern that Chagossians were not meaningfully consulted. Compensation includes a £40 million trust fund and annual grants.
Russia and China
Geopolitical Rivals
According to UK government statements, both nations view the agreement as reinforcing Western military presence in the Indian Ocean. The deal includes explicit provisions prohibiting foreign military forces on outer islands, preventing power projection from regional competitors.
UN Human Rights Experts
Special Rapporteurs (June 2025)
Called for suspension of the agreement, arguing it failed to protect Chagossian rights and contradicted their right of return. Criticized lack of provisions for cultural site access and heritage preservation.
International Legal Community
Scholars & Observers
View the agreement as a pragmatic diplomatic solution balancing sovereignty disputes with operational security needs. The deal prevents the legal uncertainty that threatened base functionality.
Mauritius Political Opposition
Prior Government Perspective
The previous Mauritian government initially agreed to the deal in October 2024. When government changed hands, new PM Navin Ramgoolam renegotiated terms, resulting in higher annual payments and additional compensation.
Strategic Implications: Why This Matters Beyond the Headlines
Understanding the geopolitical shifts and military significance
The base hosts two parallel 12,000-foot runways accommodating B-2, B-52, and B-1B heavy bombers. It provides deep-water port facilities for nuclear submarines and the largest naval vessels in the US and British fleets. Advanced satellite communication systems enable real-time command and control across vast distances. The facility has served as the launch point for major US military operations including the 1991 Gulf War and the 2001 invasion of Afghanistan.
For Mauritius, the agreement represents a diplomatic achievement after seven decades of sovereignty claims. The nation gains full control of the archipelago while securing substantial annual income. Additionally, the presence of a stable, Western-allied military installation provides indirect security benefits against regional competitors.
The China Factor (Without Oversimplification)
While some portray the deal as anti-China, the reality is more nuanced. Mauritius has strengthened economic ties with China in recent years but maintains strategic partnership with India and the West. The agreement includes explicit prohibitions on foreign military forces on outer islands, preventing any power from establishing a base near Diego Garcia. The deal reflects Western concern about China’s Belt and Road Initiative expanding military-capable port facilities across Africa and the Indian Ocean.
However, the agreement includes safeguards addressing concerns about regional power competition. The 24-nautical-mile buffer zone and joint decision-making on outer island development effectively prevent rival powers from establishing a presence near the base. According to KarmActive’s coverage of geopolitical affairs, such territorial arrangements remain central to Indian Ocean security calculations.
The Cost Conversation: Putting £3.4 Billion in Perspective
Why the price tag, while substantial, represents strategic value
The £3.4 billion figure dominates political debate, but context clarifies the decision’s logic. The UK government estimates this represents the net present value of 99 years of payments. Several comparisons illustrate the scale:
Defense Budget Impact: The annual lease represents less than 0.02% of the UK defense budget.
Operational Costs: Annual payments cost less than operating a single aircraft carrier without aircraft for one year.
Risk Mitigation: Without the agreement, international court rulings could have rendered the base legally inoperable, creating far larger strategic costs.
Compensation and Support for Chagossians
The agreement includes £40 million in trust fund support for Chagossian communities and £45 million in annual development grants for Mauritius for 25 years. The UK government has acknowledged the wrongs of the past and established resettlement provisions on islands other than Diego Garcia, where military operations must continue.
Unresolved Questions and Future Considerations
Issues that remain subject to ongoing discussion
Parliamentary Approval: The agreement was laid before Parliament in May 2025. While the 21-day objection period ended without passage of opposing motions, formal domestic implementation legislation continues through Parliament. Second reading was scheduled for September 2025.
Chagossian Rights of Return: The agreement explicitly excludes the right to return to Diego Garcia itself due to ongoing military operations. Resettlement is limited to outer islands, though environmental and security conditions apply.
Trump Administration Uncertainty: President Trump’s January 2026 criticism of the agreement raises questions about future US policy stability. However, Pentagon officials and the previous Trump administration itself endorsed the deal in 2025.
Extension Mechanisms: While the 99-year lease is extendable by another 40 years and then indefinitely, how those extensions will be negotiated remains undefined.
Environmental Management: The agreement commits both parties to preserving the Marine Protected Area, though specific enforcement mechanisms and funding details require ongoing coordination.
What the Agreement Covers
Summary of the signed accord’s provisions
The agreement transfers sovereignty of the Chagos Islands to Mauritius while preserving the Diego Garcia military base through a long-term lease. The move follows international court rulings questioning British administration and includes provisions excluding foreign military forces. The United States previously supported the arrangement before President Trump criticized it publicly. The UK government maintains that the treaty secures uninterrupted base operations and has backing from multiple allies including the Five Eyes partners, India, Japan, and South Korea.
The dispute continues amid broader tensions within NATO partnerships and reassessments of strategic positioning in the Indian Ocean. The agreement represents a diplomatic settlement balancing decolonization principles with contemporary security requirements, though debates about its implementation and long-term implications remain active.
