Britain's foreign minister, Yvette Cooper, is scheduled to meet with U.S. Secretary of State Marco Rubio on Friday in Washington, in a visit driven by concerns over defence and security cooperation after fresh criticism from U.S. President Donald Trump about the status of the Chagos Islands.
Last year, Prime Minister Keir Starmer agreed to transfer sovereignty over the Indian Ocean archipelago to Mauritius while retaining control of the atoll Diego Garcia through a 99-year lease intended to preserve U.S. activity at the base. Washington initially signalled its approval of that arrangement, but the U.S. president has since offered mixed public commentary on the matter.
Trump has publicly shifted his view several times. In January he described the deal as an act of "great stupidity." Earlier this month he acknowledged that it was the best agreement Starmer could secure, and in subsequent days renewed his criticism. On one occasion the president urged Britain emphatically not to relinquish control of Diego Garcia, writing on Truth Social, "DO NOT GIVE AWAY DIEGO GARCIA!" He added that the base could be called upon in future military operations to "eradicate a potential attack" from Iran.
The State Department, under Rubio, issued a statement on Tuesday backing the Chagos agreement, yet the following day Trump called the move a "big mistake." Under the terms that govern the joint facility, British authorities must give prior approval for any operations launched from Diego Garcia.
The island has recent operational relevance: it has been used for missions targeting Yemen's Houthi fighters and for delivering humanitarian aid to Gaza. Those activities underscore Diego Garcia's dual utility in regional military planning and relief efforts.
Reports in Britain this week suggested the president's latest public objections were linked to London not yet granting permission for the use of the bases in potential strikes against Iran, with cited concerns that such strikes might breach international law. The U.K. Ministry of Defence, when asked about that reporting, declined to comment on operational matters and reiterated that Britain supports the ongoing political process between the U.S. and Iran.
Cooper's meeting with Rubio is set against an intensifying U.S. rhetoric on Iran, with Trump warning Tehran that it must reach a deal on its nuclear programme within 10 to 15 days or face "really bad things". The diplomatic engagement in Washington will therefore cover a mixture of defence cooperation, legal and operational constraints on base use, and the wider political context surrounding Iran.
Contextual note: The forthcoming talks reflect a need to reconcile the terms of the Chagos sovereignty settlement with allied operational requirements and legal considerations - issues that the British government says will be handled within the political process.