The United Kingdom has approved an expansion of support for United States military operations against Iran, allowing American forces to use British bases for strikes targeting threats around the Strait of Hormuz.

Prime Minister Keir Starmer had previously limited US access to such bases strictly for defensive operations aimed at protecting British lives and interests. However, 10 Downing Street confirmed on Friday that ministers had broadened the scope to include operations intended to safeguard shipping routes in the strategically vital waterway.

Despite the shift, officials stressed that the UK would not be directly involved in the strikes, maintaining that its role remains within the framework of “collective self-defence.”

The move has drawn sharp reactions internationally. US President Donald Trump welcomed the decision but criticised the timing, saying Britain “should have acted a lot faster.”

Meanwhile, Iran’s Foreign Minister, Seyyed Abbas Araghchi, accused the UK government of endangering British lives and warned that Tehran views the decision as participation in aggression.

Domestically, the policy shift has triggered political backlash. Conservative leader Kemi Badenoch described it as a major reversal, while Liberal Democrat foreign affairs spokesman Calum Miller argued that Britain risks being drawn deeper into the conflict. Green Party co-leader Zack Polanski also raised concerns, calling for parliamentary approval of the decision.

The US has reportedly utilised bases including RAF Fairford in Gloucestershire and Diego Garcia in the Indian Ocean for its operations.

Tensions in the region have intensified amid threats to shipping in the Strait of Hormuz, a critical global oil transit route that previously handled about one-fifth of the world’s oil supply. Traffic through the strait has dropped significantly in recent weeks due to fears of Iranian retaliation linked to ongoing US-Israeli military actions.

A Downing Street spokesperson said ministers agreed that Iran’s actions risk further destabilising the region and worsening global economic conditions, while reiterating the UK’s call for urgent de-escalation and a swift resolution to the conflict.

The development marks a significant escalation in Western involvement, even as diplomatic efforts continue to seek a halt to hostilities.