The U.K. has denied U.S. requests to use Royal Air Force Fairford in England and Diego Garcia in the Indian Ocean for possible strikes against Iran, citing potential violations of international law, The Times reported. 

According to the report, the decision stemmed from U.K. ‘s concerns over an Iranian attack and a dispute between President Donald Trump and Prime Minister Keir Starmer over Diego Garcia’s status. 

In a post on Truth Social on Wednesday, Trump said these bases might be needed if negotiations with Iran fail. “Should Iran decide not to make a deal, it may be necessary for the United States to use Diego Garcia and the airfield located in Fairford,” Trump said. 

In the same post, Trump warned Starmer against transferring sovereignty of the Chagos Islands to Mauritius, saying it could leave Britain exposed to a potential attack from the “highly unstable and dangerous” Iranian regime.

Diego Garcia in the Chagos Islands currently hosts a strategic U.K.-U.S. military base. 

In May 2025, the U.K. and Mauritius signed a treaty to transfer sovereignty of the Chagos Islands, including Diego Garcia, to Mauritius. Under the treaty, the U.K. would lease back Diego Garcia and continue operating the joint base for at least 99 years, with possible extensions.

The treaty still requires implementing legislation in U.K. law before it fully takes effect.

The Times reported that Trump may have withdrawn his support for the U.K.’s plan to hand over control of the Chagos Islands to Mauritius after the U.K. government refused to allow the use of its military bases for U.S. bombing operations.

It remains unclear whether the President’s stance will lead to the deal’s cancellation. U.K. ministers have previously said the deal “couldn’t go ahead without U.S. support.”

Meanwhile, Trump on Thursday said the world will find out over the next 10 days whether the U.S. will reach a deal with Iran or take military action.

Trump noted that Special Envoys Steve Witkoff and Jared Kushner, his son-in-law, had “some very good meetings” with Iran. He however stressed that negotiating a meaningful deal with the country has historically been difficult. “It’s proven to be, over the years, not easy to make a meaningful deal with Iran,” he said. “Otherwise bad things happen.”

In recent days, the U.S. has moved additional military forces into the Middle East ahead of a potential strike against Iran. The Wall Street Journal reported that the current buildup of air power is the largest in the region since the 2003 invasion that launched the Iraq War.

The U.K. Defence Journal described the surge in U.S. military air activity across Europe and the Middle East as the “largest U.S. build-up of kit since the Gulf Wars.”

The U.S. assets deployed in the region include F-16s, F-22s, and F-35s, along with several aircraft carriers. According to WSJ, this buildup could sustain a much longer campaign than the U.S. strike on Iranian nuclear facilities during the Israel-Iran conflict last June.