By Taraneh Sanat
Background
Amidst rising geopolitical tension in the Persian Gulf, Westminster has found itself swept up in the changing maritime security landscape of the Indian Ocean Region (IOR). At the center of its involvement in the region is the Chagos Islands. For decades, this small archipelago has been at the heart of British defence in the Indo-Pacific, serving as the headquarters of joint US-UK military operations since the 1970s.
Its largest island, Diego Garcia, is at the forefront of such operations and has long been a signifier of the “special relationship” enjoyed between London and Washington, D.C. However, a lengthy sovereignty dispute between Mauritius, the UK, and the International Court of Justice (ICJ) may see the end of a long era of cooperation between the two allies.
In 2019, the ICJ ruled that the lawful decolonization of Mauritius would not be completed until the Chagos Islands were returned to their sovereignty. As such, the court ruled that “The United Kingdom is under an obligation to bring an end to its administration of the Chagos Islands as rapidly as possible”. Hesitant to give up a critical geostrategic post, consecutive ministers at Downing Street worked to reach a political agreement with Mauritians which allowed the British and their allies to continue defence operations on the island via a 99-year lease. The agreement has come under fire from the U.S. President Donald Trump who called the loss of British sovereignty over the island “a blight on [America’s] Great Ally”.
What Could the UK Lose?
Militarily, the UK will retain its security presence on the island through its lease agreement. This will allow the nation to continue its operational activities which the government has stated are essential to “current UK and US emergency planning and operations”. However, its ability to maintain wider regional influence will likely become limited in scope, as its activities will be confined to the leased area of the archipelago. Undoubtedly this is a concern for Westminster, as Diego Garcia is the most crucial base of British power projection in the IOR. Beyond being emblematic of strong US-UK relations, it serves as a logistic and shipping hub which connects British operations to the Indo-Pacific, Africa, and the Middle East.
These positions are key in the IOR’s current geopolitical environment. As the third largest ocean in the world, the IOR facilitates 80% of the world’s maritime oil trade and is considered critical to global energy and economic security. As a result, there has been growing political and economic influence from a wide range of actors, primarily India and China, who have been able to solidify their places as regional naval powers. Moreover, the growing military tensions between the US and Iran are based within its waters, making increased military capabilities in the region crucial to retaining global political power. As the Trump Administration has expressed dissatisfaction with the deal, there is an increasing likelihood that they will circumvent British security ventures in favour of working directly with the Mauritians. Already, Washington has sought out a direct line of communication on security matters with Mauritius. This exemplifies how the new parameters of the Chagos Deal may diminish Britain’s ability to compete strategically in this overcrowded theatre.
Regional Responses
Much has been made of the global responses and strategic changes that may come with the Chagos deal, but little attention has been paid to the opinions of indigenous Chagossians. Forcibly exiled from the island in the 1960s and 1970s, Chagossian islanders have been blocked from returning to Diego Garcia by the US and UK, despite the recent change in sovereignty. In addition, Chagossians were not consulted on the transfer of power to Mauritius or the potential for future resettlement on Diego Garcia. As a result, members of the Chagossian community have responded to the agreement unfavourably, calling it “tokenistic and superficial”.
However, despite objections from the archipelago’s indigenous community, the deal has been looked upon favourably by regional powers such as India and China. In recent years, Mauritius has strengthened partnerships with both states through strategic security agreements, meaning they stand to benefit from limitations in British sovereignty. New Delhi expressed enthusiasm for the agreement, likely viewing it as a way to increase its IOR presence to counter Chinese influence. In line with this, India launched a new airstrip and jetty in Mauritius in 2024, signalling its intention to collaborate more closely. China has mirrored these efforts for years, focusing on developing critical trade routes for Information and Communication Technology (ICT).
The combination of increased trade and strategic security efforts with Mauritius indicates that powers in the Indo-Pacific are keen to establish a strong bilateral relationship with the Mauritian government because it will have a stronger say in the future of US-UK operations across Asia. In a time of growing economic and geopolitical uncertainty, these moves can be interpreted as acts of long-term self-preservation.
Greater Implications
As of February 2025, The Chagos Deal is yet to be ratified by the British Parliament. Commentators have drawn a connection between the pause in discussions and vocal opposition of the Trump Administration to the deal. For Westminster , these concerns are crucial to consider, as they will likely have a significant impact on relations with Washington. At a time when US-Iran tensions are rapidly boiling over into gunboat diplomacy in the Persian Gulf, Diego Garcia and the greater network of the Chagos Islands are an essential diplomatic tool to leverage with the Trump Administration and vital strategic asset to be guarded against competing regional interests. As the ICJ ruling cannot be circumvented by the UK or the US, it must be looked at as the regulatory outline for future operations across the IOR and be acknowledged as a critical shift in British influence over the Indo-Pacific and Asia at large.
Image from The Asahi Shimbun via Getty Images