The United Kingdom has reportedly refused a United States request to use British military bases for a potential strike on Iran, in a move that could strain relations between London and Washington.
According to The Times, Prime Minister Sir Keir Starmer informed US President Donald Trump that the UK would not permit American forces to use facilities at Diego Garcia — the joint US-UK base in the British Indian Ocean Territory — or RAF Fairford in Gloucestershire for military action against Iran.
The report suggests the decision was driven by concerns that participating in a strike without a clear legal mandate could breach international law.
Under longstanding defence agreements, the United States must seek British approval before launching operations from UK sovereign bases.
The alleged refusal is said to have angered President Trump, who reportedly withdrew support for UK proposals to transfer sovereignty of the Chagos Islands — including Diego Garcia — to Mauritius.
Diego Garcia is considered one of the most strategically significant US military outposts in the Indo-Pacific region. Several UK media outlets, including the BBC, have reported that heightened US preparations for possible strikes on Iran have underlined the island’s military value.
President Trump referenced the base directly in a post on Truth Social, writing: “Should Iran decide not to make a deal, it may be necessary for the United States to use Diego Garcia, and the [RAF] Airfield location in Fairford, in order to eradicate a potential attack by a highly unstable and dangerous regime.”
RAF Fairford and other UK facilities were recently used by US forces during an operation involving the tanker Bella 1, which was accused of breaching sanctions linked to Iran’s so-called “shadow fleet”. The UK Ministry of Defence confirmed last month that operation had full British backing and was conducted within international law.
However, potential pre-emptive military action against Iran would likely face significant political and legal scrutiny in Westminster.
The Times reported that UK officials would be unlikely to support a strike similar to a previous US attack on Iranian nuclear facilities during last summer’s 12-day conflict involving Israel and Iran.
Neither the UK Government nor the White House has formally commented on the latest reports.
Tehran has responded sharply to the possibility of military escalation.
In a letter addressed to UN Secretary-General António Guterres and the President of the UN Security Council, Iran’s ambassador to the United Nations, Amir Saeid Iravani, warned that US military facilities in the region would be considered “legitimate targets” in the event of an attack.
The letter urged the international community to “ensure that the United States immediately ceases its unlawful threats of the use of force.”
It added that Iran remains committed “to diplomatic solutions” and “on a reciprocal basis, addressing ambiguities regarding its peaceful nuclear programme.”
However, Iravani cautioned that if Iran were subjected to military aggression, “all bases, facilities, and assets of the hostile force in the region would constitute legitimate targets in the context of Iran’s defensive response.”
President Trump has repeatedly raised the prospect of military action against Iran, citing both Tehran’s handling of domestic unrest and concerns over its nuclear programme.
On Thursday, he reportedly stated that Iran had no more than 15 days to reach an agreement, again suggesting strikes could follow if diplomatic efforts fail.
Recent indirect talks in Geneva between US envoy Steve Witkoff and intermediaries linked to Iran’s top diplomat reportedly showed tentative signs of progress.
As tensions escalate, the reported UK refusal to grant access to Diego Garcia and RAF Fairford underscores the delicate balance London faces between its strategic alliance with Washington and adherence to international legal principles.