The United Kingdom has launched an informal review of its 2025 sovereignty agreement that would cede control of the Chagos Islands to Mauritius, UK Defence Secretary Wes Streeting has confirmed, following renewed public criticism of the pact from US President Donald Trump at the United Nations General Assembly this week.
The original deal, negotiated and signed under former UK Prime Minister Keir Starmer in May 2025, was designed to resolve a decades-long sovereignty dispute over the Indian Ocean archipelago. Under its terms, the UK would transfer full sovereignty of the islands to Mauritius in exchange for a 99-year lease on the strategic UK-US military base located on Diego Garcia, the archipelago’s largest island. The UK government initially projected the total net cost of the agreement at £3.4 billion, or roughly £101 million ($136 million) in annual payments to Mauritius, though political opponents have argued inflation-adjusted costs could reach as high as £35 billion, with additional risks of expanded Chinese influence in the region.
The agreement hit a deadlock in April of this year when Trump withdrew US support, forcing the Starmer administration to pause the deal indefinitely ahead of its parliamentary ratification. Streeting made clear in comments to BBC Breakfast on Wednesday that the review is a direct response to Washington’s opposition, noting that Trump’s recent public criticism clarified his unchanged stance on the unamended draft. “What President Trump said yesterday wasn’t new but I think it does provide absolute clarity that his position on this Chagos deal as currently drafted is not changing,” Streeting told reporters. “So we have to do more work with our American allies, with President Trump and his administration, to get the deal to a place where he can support it.”
The Diego Garcia base has long been viewed as one of the West’s most critical strategic assets in the Indian Ocean, giving UK and US military forces unmatched access to a region that has grown in geopolitical importance in recent decades. Successive UK prime ministers have held that the ongoing unresolved sovereignty dispute, which has backing from international courts, puts the long-term security of the base at risk. Streeting emphasized that the core priority of the ongoing review is to secure long-term stability and certainty for the base’s operations.
The renewed public scrutiny of the deal came during Trump’s first in-person meeting with current UK Prime Minister Andy Burnham on the sidelines of the UN General Assembly in New York, where Trump publicly called the agreement “terrible” and stated the UK would revisit the terms. Burnham simply replied “Yep” during the exchange, and later clarified to reporters that his government inherited the negotiations and is committed to finding a workable resolution that protects the base’s future. “It’s critical to safeguard the future of the base, and that matters to us for security reasons, but also clearly to the United States as well,” Burnham said. “What I said in the meeting is that we will work to find that resolution between the different sides, and we’ll work hard to find it.”
Ahead of his UN trip, Burnham spoke with Mauritian Prime Minister Navin Ramgoolam, and an official readout of the conversation confirmed Burnham “reiterated his commitment to continue doing everything possible” alongside the US to advance the deal toward ratification. Downing Street sources have stressed that the current review does not represent a major policy shift from the previous position, which has always required US backing to move forward, though Streeting’s comments marked the first explicit public confirmation that the unamended draft cannot gain Trump’s support. Officials added that the review is not a formal, time-bound process, and no public funds will be transferred to Mauritius while the assessment is underway.
Political opposition figures have seized on the review to call for the entire deal to be scrapped. Conservative Party leader Kemi Badenoch urged Burnham to abandon the agreement entirely, calling it a “terrible deal” that serves no UK national interest. Reform UK leader Nigel Farage went further, declaring “The Chagos deal is dead. Thank God.”
The dispute over the Chagos Islands dates back to 1965, when the UK separated the archipelago from Mauritius ahead of granting Mauritius independence, a move Mauritius has long argued was illegal. In 2019, the International Court of Justice (ICJ) issued a non-binding advisory opinion confirming the separation was unlawful and calling on the UK to end its administration of the islands as quickly as possible. The UN General Assembly endorsed the opinion, strengthening Mauritius’ sovereignty claims and pushing the UK to open formal negotiations in 2022.
Streeting told BBC Radio 4’s Today programme that the goal of the current process is to find a compromise that can be accepted by all stakeholders. “Describing the Diego Garcia base as “one of the most sensitive and valuable national security assets”, he said work was underway to find a deal “that maybe not everyone loves, but everyone can live with.”