Keir Starmer’s decision to hand over sovereignty of the British-owned Chagos Archipelago, which hosts the crucial United States and United Kingdom military base at Diego Garcia, has provoked deep concern among defence analysts, diplomats and senior parliamentarians on both sides of the Atlantic.
Critics warn that the move could undermine Western security interests across the Indian Ocean, potentially opening the door to Chinese and Indian strategic influence in one of the world’s most sensitive maritime zones.
Mauritius, a country with close financial and political ties to both India and China, signed a wide-ranging defence cooperation agreement with New Delhi during an eight-day visit by Prime Minister Navinchandra Ramgoolam to India in September. According to reports in The Economic Times and The Times of India, the agreement includes Indian naval access to the Chagos Islands, permission to conduct hydrographic surveys, and plans to build a satellite tracking facility “near the Diego Garcia United States and United Kingdom base”. Indian media have described the planned installation as a “strategic asset for monitoring the region”, terminology commonly used for intelligence-gathering operations.
While the precise site for the Indian facility has not been confirmed, analysts point out that similar infrastructure has already been established on Agaléga, another Mauritian island now hosting what amounts to an Indian military outpost.
Mauritius’s growing reliance on India’s economic and diplomatic support, coupled with its significant indebtedness to China, has deepened concerns that the archipelago could become a contested geopolitical space. “Mauritius is balancing on a knife edge between India and China,” one senior British defence official said. “Placing Diego Garcia under Mauritian sovereignty introduces enormous uncertainty about the long-term security guarantees that underpin United States and United Kingdom operations there.”
A Fragile Security Balance
Under the terms of the May 2025 sovereignty agreement, the United States will continue operating its Naval Support Facility at Diego Garcia under a lease-back arrangement once Britain formally winds down the British Indian Ocean Territory administration. The treaty has not yet been ratified, and members of the House of Lords are expected to challenge several provisions in a debate scheduled for Tuesday.
The base at Diego Garcia has long served as a linchpin of Western military operations, supporting global logistics, reconnaissance, and deterrence missions. Its isolation, nearly 1,000 miles from the nearest continental landmass, has historically ensured security from both regional and state-sponsored threats. However, the situation is changing rapidly.
Recent intelligence assessments indicate that Iran has tested long-range drones and missiles potentially capable of reaching Diego Garcia, while China’s expanding naval footprint in the Indian Ocean has heightened strategic competition. The possibility that non-allied states might gain indirect access to the Chagos region through Mauritius is viewed by defence planners as a serious emerging risk.
Political Fallout in London and Washington
The handover deal has already become a flashpoint in Westminster. Attorney General Lord Hermer and Labour’s chief negotiator Jonathan Powell are under scrutiny following allegations that sensitive security concerns were sidelined during the negotiations. Former United States Secretary of State Mike Pompeo went so far as to call Powell “strategically an absolute fool”, warning that “Mauritius is a close ally of the Chinese Communist Party, and if Diego Garcia is lost, Chinese power projection will reach the heart of the Indian Ocean”.
Opposition parties in the United Kingdom have pledged to review or even reverse the deal if they come to power. “This treaty weakens Britain’s hand and endangers the Western alliance’s most important Indian Ocean base,” said one Conservative MP. “It is unthinkable that the Government is proceeding without full parliamentary scrutiny of the security consequences.”
Reform UK leader Nigel Farage has declared that, if elected, he would “simply refuse to pay”, calling the handover “a betrayal of British sovereignty and common sense”. Yet defence analysts warn that such a move could be even more dangerous.
“One of the few things that could make Beijing happier than this handover would be for Britain to renege on it,” said one senior defence expert. “A British default would hand China a propaganda victory, give Mauritius justification to expel the United States and the United Kingdom from the islands, and could unravel the entire security architecture of the Indian Ocean. It would be the single greatest strategic blunder of the century.”
Unanswered Questions
Key issues remain unresolved. It is unclear whether the new Mauritian administration would permit United Kingdom or United States defensive infrastructure to be expanded to nearby islands such as Peros Banhos, which could serve as air defence or early warning sites. Nor has any provision been made to guarantee the continuation of the 250,000 square mile Marine Protected Area patrolled by British forces, a zone that currently acts as both a buffer and an early warning perimeter for Diego Garcia.
With geopolitical tensions in the region rising and the future of Diego Garcia’s security architecture in doubt, critics argue that the United Kingdom is surrendering not only territory but strategic foresight. “We are effectively paying to lease back our own base,” said one former defence minister. “It is an extraordinary act of short-term thinking that could reshape the balance of power in the Indian Ocean for decades.”
Claire Bullivant
