Donald Trump could order airstrikes on Iran from the British overseas territory of Diego Garcia without asking for permission from the UK government, Downing Street acknowledged on Tuesday.

The US deployed six long-range B-52 bombers to the Indian Ocean base as part of its preparations for possible conflict with Iran in the aftermath of the killing of Qassim Soleimani.

No orders have been given yet to strike but Mr Trump has threatened to hit 52 Iranian targets, including cultural heritage sites, if Iran attacks US forces in retaliation for Soleimani’s death.

The US runs a secretive air base from Diego Garcia and the British government has little to no control on what operations the American military runs from the island.

Downing Street admitted that Mr Trump could order strikes on Iran from the island without seeking permission from Britain. “It is provided for under existing agreements,” a spokesman said.