Mauritius is hopeful that the deal to transfer sovereignty of the Chagos Islands from the UK will be concluded after US President Donald Trump provisionally signalled his backing while warning that any breach of the deal could bring a US military response.
“I understand that the deal (UK) Prime Minister (Keir) Starmer has made, according to many, (is) the best he could make,” Trump wrote on his “Truth Social” platform.
“However, if the lease deal, sometime in the future, ever falls apart, or anyone threatens or endangers U.S. operations and forces at our Base, I retain the right to Militarily secure and reinforce the American presence in Diego Garcia. Let it be known that I will never allow our presence on a Base as important as this to ever be undermined or threatened by fake claims or environmental nonsense.”
Trump’s latest about-turn came just weeks after he called the agreement ‘an act of great stupidity’ on his Truth Social platform last month, itself a previous reversal of his administration’s support for the deal. UK government figures have previously said they will not go ahead with the deal without US approval.
The agreement secures for the UK an initial 99-year lease for the strategically important UK-US military base on Diego Garcia. The BBC reports that the UK will pay £165m ($224m) in each of the first three years. From years four to 13, it will pay £120m ($160m) a year. After that, payments will be linked to inflation.
Betting on lawfare
Mauritius’s coalition government, led by Navin Ramgoolam, remains determined to reverse a decision made six decades ago. His father, Seewoosagur Ramgoolam, the country’s first prime minister, agreed to the 1965 excision of the archipelago from the colony of Mauritius only after it was made a prerequisite for independence.
While Trump stokes political turbulence, Ramgoolam is betting on lawfare over rhetoric, with an ally in Britain’s Prime Minister Keir Starmer, a staunch defender of the “rules-based international order”. Domestic support in Mauritius for the sovereignty claim is unanimous. Ramgoolam’s main political rival, Pravind Jugnauth of the MSM, having suffered a comprehensive 2024 electoral defeat, played a leading role in the legal challenges mounted against the UK.
For Mauritius, the Chagos claim has evolved from a moral grievance to what it sees as a test of international legitimacy and national confidence. While pursuit of the claim was relatively weak in the immediate years following the country’s independence in 1968, an economically successful Mauritius – now ranked as an upper-middle-income country by the World Bank, powered by tourism, textiles, ICT and offshore finance – can afford to flex its muscles and assert itself as a strategic hub between Africa and Asia.
What’s more, Olivier Bancoult, leader of the Chagos Refugees Group, who continues to represent the majority of Chagossians in Mauritius, kept the issue alive through UK court battles starting in the late 1990s, galvanising a Mauritian political class stocked with British and French-trained lawyers. By framing the Chagos claim within broader global decolonisation narratives, the campaign built cross-community support, enabling traditionally Hindu-dominated parties, including the Labour Party and the MSM, to extend their reach to Afro-Creole communities – who make up just over a quarter of the population – and shore up critical coalitions.
The legal campaign entered a decisive phase in December 2010, when Ramgoolam’s government successfully challenged the UK’s creation of a marine protected area (MPA) under the UN Convention on the Law of the Sea (UNCLOS). By 2015, an international tribunal ruled the MPA unlawful. This strategic manoeuvre paved the way for the 2019 International Court of Justice (ICJ) advisory opinion, which declared that Britain’s detachment of the Chagos Archipelago was unlawful, and deemed Seewoosagur Ramgoolam’s colonial-era consent for the carve-out invalid.
Though non-binding, the ruling carried huge symbolic and political weight. London feared that further decisions would call into question the UK’s presence, jeopardising the long-term viability of the UK-US Diego Garcia military base. There were also mounting concerns that without a formal treaty, a vacuum could open the door for expanded Chinese presence in the Indian Ocean – stretching through fishing fleets that double as surveillance platforms to the threat of naval facilities on the archipelago’s outer islands. Starmer’s Labour government finalised the sovereignty transfer, citing the need to lock in a permanent veto over foreign military activity, a move initially approved by both the Biden and Trump administrations – until now.
UK right mobilises against deal
Part of the recent difficulties stems from Trump’s revived nationalist rhetoric – the same impulse behind his declaration that Greenland should become US territory – paired with a more strained rapport with Starmer. Another complicating factor is Nigel Farage’s growing influence. His party, Reform UK, after surging in recent polls, has found a receptive audience in Washington. Astutely courting UK-based Chagossian groups, who are opposed to the transfer, Farage persuaded US treasury secretary Scott Bessent that Mauritius’s claim to the islands is both geographically and historically tenuous.
He argues that the 1,350 miles separating Port Louis from Chagos severed any meaningful colonial administrative, economic and social links, and that contemporary geopolitics should shape UK-US policy rather than decolonisation precedents. The opposition Conservatives, led by Kemi Badenoch, also oppose the deal and have been lobbying Washington to scrap it.
An anxious wait
For Port Louis, there is a clear advantage in maintaining public restraint over the treaty, which remains unratified by the UK parliament. Recent developments suggest the situation remains fluid: Prime Minister Starmer faces significant domestic political turmoil that could derail the parliamentary push.
Nevertheless, by avoiding a running commentary – or worse, an open confrontation – Mauritius hopes that the UK and USA will resolve any remaining differences on the issue and deliver up the islands to Mauritian sovereignty.
Seán Carey is an honorary research fellow in the School of Social Sciences, University of Manchester.