British authorities have refrained from authorising the United States to employ facilities on British territory for any prospective strike against Iran, sources familiar with the matter say. The holdback specifically includes the Diego Garcia military base in the Chagos Islands and an airfield in England that were named by the U.S. president as possible staging points.
The announcement of withheld permission comes amid a U.S. concentration of military assets in the Middle East and heightened pressure on Tehran while negotiations over its nuclear programme continue. The U.S. president publicly noted that the Indian Ocean base and an English airfield could play key roles in a hypothetical U.S. military action.
Those with knowledge of the UK government’s stance told reporters that London has not granted the requested access because of concerns tied to international law and other considerations. The same sources noted that Diego Garcia was not used by U.S. forces during strikes on Iran that took place in June.
Diplomatic communications between the two leaders have continued. The U.S. president and Prime Minister Keir Starmer spoke by telephone on Tuesday to discuss the Iran-US talks being held in Geneva. The official readout of that call did not indicate whether the U.S. president had formally asked for use of British bases.
The discussion over base access is unfolding alongside a separate diplomatic dispute about sovereignty over the Chagos Islands. On Wednesday, the U.S. president criticised the proposed transfer of control of the Chagos Islands to Mauritius, calling it a "big mistake." That comment marked a reversal from remarks he made two weeks earlier when he described the agreement as the "best" option the UK prime minister could reach. The later criticism came one day after the U.S. State Department had publicly endorsed the transfer.
Implications of London’s decision remain uncertain. The UK’s cited concerns about international law underscore legal and diplomatic constraints that can limit allied military cooperation, even amid elevated regional tensions and military deployments. The refusal also highlights how shifting political statements and diplomatic endorsements can create ambiguity about allied positions on territorial and basing arrangements.
For now, available information indicates that Diego Garcia was not used during the June strikes and that no formal permission has been given for its use in any future strike on Iran. Officials have continued high-level contact, but public readouts have not clarified whether base access was requested during recent calls. The debate over the Chagos transfer adds a further layer of diplomatic complexity to UK-US military interactions.
Given the limits of the current reporting, further details about the specific legal considerations cited by the UK and whether additional bases are affected were not provided by the sources.