The British government has formally shelved its controversial plan to hand sovereignty of the Chagos Islands to Mauritius, in what critics are calling one of the most significant foreign policy climbdowns in recent memory. Prime Minister Keir Starmer has pulled the treaty from the parliamentary schedule after sustained pressure from Washington, with President Donald Trump having made clear his fierce opposition to any deal that could compromise the strategic US military base at Diego Garcia.
What Was the Chagos Islands Deal?
The Chagos Islands, a remote British Overseas Territory in the Indian Ocean, have been at the centre of a long-running sovereignty dispute between the United Kingdom and Mauritius. The archipelago is home to Diego Garcia, one of the most strategically significant military installations in the world — a joint US-UK naval and air base that has played a pivotal role in operations across the Middle East, Central Asia, and the wider Indo-Pacific region.
Under a preliminary agreement signed by both governments in May 2025, the UK agreed to transfer sovereignty of the islands to Mauritius in exchange for a 99-year lease allowing continued military operations at Diego Garcia. The deal was hailed by its architects as a pragmatic resolution to a dispute that had dragged through international courts and damaged Britain’s standing among developing nations. Critics, however, warned that surrendering sovereignty over territory of such strategic value was a serious error.
Trump’s Fierce Opposition
From the moment he returned to the White House, Donald Trump made his views on the Chagos deal unmistakably clear. In January 2026, he denounced the agreement as an “act of great stupidity” and “total weakness,” arguing that handing control of the islands to Mauritius — a country with close ties to China — posed an unacceptable risk to Western security. The US, as the primary operator of Diego Garcia, had never formally given its blessing to the deal, and Trump’s intervention effectively ended any realistic prospect of parliamentary ratification.
The episode placed Starmer in a deeply uncomfortable position. His government had invested considerable diplomatic effort in reaching the agreement and had defended it vigorously in the face of domestic opposition. With Washington now actively hostile to the plan and Conservative opposition seizing on the crisis, the Prime Minister faced an increasingly impossible calculation.
The King’s Speech Snub
The most concrete indication that the deal was dead came with confirmation that the legislation required to implement the treaty would not be included in the King’s Speech — the formal parliamentary programme through which the government sets out its legislative priorities. Without a bill passing through both Houses of Parliament, the treaty cannot be ratified under UK law.
The decision represents a significant setback for Starmer’s foreign policy ambitions and raises questions about Britain’s ability to pursue an independent diplomatic agenda in the face of American pressure. Several senior figures within the Labour Party have expressed private frustration at what they see as an unnecessary capitulation to a Trump administration with which the government has otherwise sought to maintain careful working relations.
Mauritius Threatens Legal Action
Mauritius has not taken the British retreat lying down. Senior Mauritian officials have threatened legal action against the UK government, arguing that Britain’s failure to ratify an agreement it had formally signed represents a serious breach of international obligations. The threat of arbitration proceedings adds a further layer of complexity to an already fraught situation and could result in years of costly and politically damaging litigation.
What Happens to Diego Garcia Now?
In the short term, the operational status of Diego Garcia is unchanged. Britain retains sovereignty over the islands, and the base continues to function under existing arrangements. However, the underlying legal uncertainty created by the 2019 International Court of Justice advisory opinion — which found that Britain’s separation of the islands from Mauritius during decolonisation was unlawful — has not been resolved. That ambiguity will continue to complicate long-term planning for the base and could resurface at any point.
For now, Starmer’s government finds itself having pleased neither Washington fully — since the underlying dispute remains unresolved — nor Mauritius, which retains its legal claims. It is, as one former Foreign Office official noted, a situation that leaves Britain in the worst of all possible worlds.
Political Fallout at Home
The collapse of the deal has provided the Conservative opposition with fresh ammunition. Shadow Foreign Secretary Kemi Badenoch described the episode as emblematic of a government that “lurches from one foreign policy crisis to the next,” while Reform UK used the controversy to renew calls for a more assertive approach to British sovereignty issues. For a government that came to power promising competent, stable governance, the Chagos retreat has reinforced a damaging narrative of drift.