UK Defence Secretary Wes Streeting said a treaty with Mauritius over the Chagos Archipelago lacks President Donald Trump's backing, complicating a plan to secure long-term use of a major U.S. military base.
Streeting told a parliamentary committee Oct. 13 that a settlement needed the support of Britain, Mauritius and the U.S. president. The treaty, signed May 22, 2025, has not taken effect. Parliament's 2024-26 session ended April 29, and the bill to implement the agreement has made no further progress since then.
Mauritius set out its position in an Oct. 14 statement about a meeting held Oct. 2. At that meeting, Mauritian Prime Minister Dr Navinchandra Ramgoolam told UK National Security Adviser Jonathan Powell that sovereignty over the archipelago, including Diego Garcia, was nonnegotiable. Mauritius said legal action would be inevitable unless the matter was resolved promptly.
The agreement would recognize Mauritius as sovereign over the islands while allowing Britain to operate the Diego Garcia base jointly with the United States for 99 years after the treaty takes effect. The two countries could agree to extend that arrangement for another 40 years. Britain estimates its payments to Mauritius would average £101 million annually, with a net present value of £3.4 billion. Payments have not begun.
Diego Garcia's airfield and harbor help supply U.S. forces operating in the Indian Ocean and Arabian Gulf, according to the U.S. Navy. The UK Ministry of Defence says the island's port, communications and surveillance facilities support operations across the Middle East, East Africa and South Asia.
The base drew attention in March when then-UK Defence Secretary John Healey told Parliament that two missiles had been launched toward it on March 20. One fell short and the other was brought down before reaching the island, he said. Healey blamed Iran; Iranian Foreign Ministry spokesperson Esmaeil Baqaei challenged that attribution. Healey said neither missile came close and base operations continued.
Britain separated the Chagos Archipelago from Mauritius in 1965, before Mauritian independence. In a 2019 advisory opinion, the International Court of Justice found that Mauritius' decolonization had not been lawfully completed and called for Britain to end its administration of the islands without delay.
The treaty provides a £40 million trust fund for Chagossians and permits resettlement on islands other than Diego Garcia. A House of Lords committee found differing views among Chagossians, including concern about exclusion from Diego Garcia and demands for a greater say in resettlement and trust fund decisions.
A separate bill that would restrict a transfer of sovereignty is scheduled for a House of Lords second reading Oct. 23. That reading would not bring the treaty into force.
