The Chagos Impasse

Editorial

The long dispute over the Chagos Archipelago has reached a strange deadlock. In May 2025, after years of hard diplomatic work, the UK and Mauritius signed a historic agreement meant to end one of the last remnants of British colonial rule. Under this deal, London recognised Mauritian sovereignty over the islands, while Port Louis agreed to lease Diego Garcia back to the UK and US for 99 years to protect the key military base. It was celebrated as a practical success: international law was respected, Mauritian sovereignty was restored, Chagossian resettlement was advanced, and Western security interests in the Indian Ocean were preserved.  

Today, however, that balanced agreement is frozen in political paralysis. The UK implementation bill was paused in the House of Lords in January 2026 and remains completely stuck. The main reason for this delay is not a quarrel between London and Port Louis, but sharp criticism from Washington, where US President Donald Trump again called the treaty a “terrible” deal.  

As David Snoxell, former British High Commissioner and APPG Coordinator, notes in this week’s interview, this mess comes from missed opportunities and unnecessary political delays. What should have been a smooth approval process has turned into a heated debate, leaving the UK, Mauritius, and Chagossian-born Mauritians stuck in uncertainty. 

The Cost of Delay and Domestic Politics

This crisis dates back to November 2022, when Britain and Mauritius first pledged to negotiate a treaty based on international law. If those talks had wrapped up quickly, the treaty likely would have been approved long before the 2024 elections brought new leaders and shifting priorities to London, Washington, and Port Louis.  

Instead, a nearly four-year gap between the initial announcement by former Foreign Secretary James Cleverly and the final May 2025 signing allowed political opposition to grow strong. In the UK, conservative think tanks, media figures, and some MPs attacked the deal as a surrender. Meanwhile, disagreements among Chagossian groups in the UK — some feeling left out of the process — made passing the law even harder.

These internal disagreements hurt the APPG as well, which lost several members after the 2024 UK election. Still, David Snoxell stresses that the main APPG leadership remains firmly committed to a negotiated deal and Chagossian resettlement. At its 104th meeting in June, the group expanded its mission to secure a fair return process for Chagossians. The key now is stopping election cycles from destroying that goal.  

Dealing with Washington’s Ambivalence

The main challenge for London and Port Louis is balancing Mauritian sovereignty with opposition from the US President Trump. David Snoxell emphasizes a key point: Britain does not face opposition from the broader US government. The US military, State Department, and national security agencies support the treaty because the 99-year lease secures the Diego Garcia base. The pushback comes almost entirely from President Trump himself.  

Yet, because the 1966 UK–US agreement requires Britain to keep control of the territory, London feels it cannot approve the treaty without the US President’s consent. This creates a major dilemma for British diplomats.  

Mauritian Prime Minister Navin Ramgoolam has stated clearly that Mauritian sovereignty is non-negotiable and the treaty text cannot be reopened. With Port Louis standing firm, Britain has little room to manoeuver. Waiting for the next US administration in January 2029 is very risky, as new governments and changing world events could destroy the consensus completely.  

Reimagining the Framework: The Trilateral Path

If changing the treaty is impossible, how can this deadlock be broken? One practical idea gaining support in London is a three-way side-agreement between the UK, US, and Mauritius.  

This setup keeps the transfer of sovereignty intact while giving Washington extra guarantees about the base. A three-way agreement is likely to satisfy everyone’s interests: it lets Britain fulfil its 1965 promise to return Chagos to Mauritius, just as it returned the Aldabra Islands to Seychelles in 1976. It leaves the 56 Outer Islands under Mauritian rule for Chagossian resettlement and allows the Marine Protected Area to win international recognition.  

For the US, a three-way deal guarantees full military use of Diego Garcia in exchange for lease payments to Mauritius, saving British taxpayers from funding a base they do not use.   Some US critics argue that even a 99-year lease creates long-term uncertainty. But David Snoxell notes that looking past 2127 ignores tech and environmental realities. By 2127, long-range weapons may make distant military bases unnecessary — shown by recent direct US strikes launched from the American mainland. More urgently, rising sea levels could make the low-lying Diego Garcia base unusable well before the lease ends. Demanding terms beyond a century makes no sense.  

The Imperative of International Law

If the UK gives in to Washington’s doubts and lets the treaty fail, its global reputation will suffer heavily. For years, Britain’s standing as a defender of international law has been damaged by ignoring the 2019 International Court of Justice (ICJ) opinion and UN resolutions calling for an end to its colonial rule.   British control over the islands is already weakening fast. UK control over Chagos waters, fishing rights, and environmental rules is no longer respected. The territory cannot issue recognized stamps or coins, and the UK faces losing its coastal seat on the Indian Ocean Tuna Commission.  

If the treaty stays stuck, Mauritius will surely take the fight back to the UN, the ICJ, and ITLOS. Britain would find its legal and diplomatic position impossible to defend.   As Margaret Thatcher told Parliament in 1980, official UK policy has long been that when the islands are no longer needed for defence, they must return to Mauritius. The May 2025 treaty respects that principle while safeguarding military requirements. Given the growing militarisation of the Indian Ocean by various powers, US interest in the Diego Garcia base is unlikely to wane anytime soon — in fact, it may become even more vital than it is today. It is now up to the Mauritian government to explore whether three-way arrangements could help unlock the present stalemate, convince Washington of the deal’s strategic value, and close this colonial chapter for good.

Mauritius Times ePaper Friday 2 October 2026