The UK says it is ready to defend itself after Tehran warned bases used by US forces could be targeted

Britain has said it is ready to defend itself after Iran warned that UK bases used by American forces could be treated as legitimate targets.

Iran’s warning to the UK has raised concern that the widening conflict between Washington and Tehran could move closer to British-controlled territory. Ministers insist the UK is not seeking a broader war and say any support for the US is limited to defensive operations carried out in line with international law.

The warning centres on British-linked military sites that host US personnel and aircraft, including RAF Fairford in Gloucestershire and Diego Garcia in the Indian Ocean. The UK has previously allowed the US to use such bases for defensive operations connected to Iranian attacks on Gulf states and shipping in the Strait of Hormuz.

Iran’s foreign ministry accused Britain of acting as an accomplice in the US campaign. The Islamic Revolutionary Guards Corps also warned that any country offering military support to Washington would be responsible for the consequences.

A UK government spokesperson said the armed forces were prepared to protect the country from threats at home or abroad. The statement pointed to Britain’s layered air and missile defences, involving the Royal Navy, British Army and Royal Air Force, working with Nato allies.

Iran’s UK warning comes as the US continues repeated strikes on Iranian targets. US Central Command said its latest operations were intended to weaken Iran’s ability to threaten civilian crews and commercial vessels in regional waters. Washington says the Strait of Hormuz remains open, although shipping through the route has come under severe pressure.

The UK Ministry of Defence has not confirmed whether RAF Fairford was used in the latest US operations against Iran. Iranian-linked media claimed American bombing missions had recently launched from the base, but that claim has not been independently verified.

The issue is politically sensitive for Prime Minister Andy Burnham, who has inherited the policy from Sir Keir Starmer. The UK is trying to draw a clear line between helping an ally defend regional shipping and becoming directly involved in offensive action against Iran.

That line is now under pressure. Tehran appears to be arguing that allowing US aircraft to operate from British-linked sites makes the UK part of the campaign. London rejects that position and says its focus remains protecting British people, interests and allies without being dragged into a wider conflict.

Iran’s warning to the UK over bases used by US forces has also brought Diego Garcia back into focus. In March, Iran fired two ballistic missiles towards the UK-US base in the Chagos Islands. One reportedly failed during flight, while the other was shot down by a US warship. At the time, there were questions about the range, accuracy and reliability of Iran’s missile systems.

Analysts have also raised doubts about whether Iran could reliably strike the UK mainland. Israel has previously claimed Iran has missiles with enough range to reach parts of Europe, but British officials have not publicly confirmed a specific threat to the UK itself.

Even so, the threat has shifted attention back to Britain’s air and missile defences. Any attempted attack on British territory, or on a UK-controlled base, would mark a serious escalation and could force London into a more direct role.

Iran’s warning to the UK is being made against a backdrop of continuing attacks on shipping in the Strait of Hormuz. Iran has targeted vessels and Gulf states that host US forces, while Washington says its strikes are intended to protect commercial traffic through one of the world’s most important energy routes.

For now, Britain is trying to project readiness without sounding eager for confrontation. Ministers are stressing defence, restraint and coordination with allies. Iran, meanwhile, is using the presence of US forces at British-linked bases to increase pressure on London.

The danger is that a conflict Britain says it wants to avoid could still reach British-controlled territory. As US strikes continue and Tehran’s threats become more direct, Iran’s warning to the UK has turned into a serious diplomatic and security flashpoint in the Gulf crisis.