U.S. Rejects UK-Mauritius Deal Over Chagos Islands in Stunning Reversal

A dispute over the Chagos Islands has intensified after the U.S. reversed its stance on a UK-Mauritius agreement. Initially backed in May 2025, the deal would have secured the Diego Garcia military base under a 99-year lease. But in January 2026, President Trump condemned the arrangement as 'great stupidity' and threatened to use force to retain control of the base.

The shift comes as the UK faces pressure over the islands' future, with the UN criticising the treaty's ethical failings and the U.S. warning against its ratification.

The Chagos Islands, home to the strategically vital Diego Garcia base, have long been jointly managed by the UK and U.S. under a lease requiring American approval for military operations. The UK initially agreed to transfer sovereignty to Mauritius in 2025, a move the U.S. first supported. However, President Trump later rejected the plan, calling it flawed and insisting the U.S. would defend its base rights 'by force if necessary.'

The U.S. Ambassador to the UK, Warren A. Stephens, had previously described the transfer as the best available option. But concerns grew over ceding territory to Mauritius, a nation with ties to China, while the UK remains a key ally. The UN Committee on the Elimination of Racial Discrimination also urged both countries to halt ratification, citing ethical shortcomings.

A proposed alternative would grant the displaced Chagossian people a self-determination referendum. If they chose to resettle as a British Overseas Territory, the legal status of Diego Garcia—and the entire archipelago—would be secured. This approach, advocates argue, would offer four key benefits: preserving UK sovereignty, addressing historical injustices, redirecting funds to NATO, and bolstering Britain's moral standing.

The President has repeatedly criticised the lease terms as weak, while U.S. officials have dismissed the UN's non-binding advisory judgment on the islands. Now, Washington is pushing London to abandon the Mauritius Treaty and pursue the referendum-based solution instead.

The deadlock leaves the UK under pressure from both the U.S. and international bodies. If the Chagossians vote for resettlement under British rule, the islands' legal status would stabilise, easing tensions over Diego Garcia. For now, the base remains under joint control—but the threat of U.S. intervention looms if the current treaty moves forward.