Sir Keir Starmer has issued a joint statement with the leaders of France, Germany, Italy, the Netherlands and Japan condemning Iranian attacks on vessels and the blockade of the Strait of Hormuz.
The leaders expressed their “deep concern” about the escalating conflict, calling on Iran to “cease immediately its threats, laying of mines, drone and missile attacks, and other attempts to block the strait to commercial shipping”.
It comes after UK defence secretary John Healey vowed to “step up” defensive support for Gulf states after Iran attacked energy sites across the region in a “serious escalation” of the war.
The price of Brent crude oil was rising by about 7 per cent to cross $114 (£85) a barrel on Thursday morning, meaning it was closing in on the highest level since the conflict escalated at the end of February, heightening fears about major disruption to global supplies.
In a statement, the six leaders said: “We condemn in the strongest terms recent attacks by Iran on unarmed commercial vessels in the Gulf, attacks on civilian infrastructure including oil and gas installations, and the de facto closure of the Strait of Hormuz by Iranian forces.
“We express our deep concern about the escalating conflict. We call on Iran to cease immediately its threats, laying of mines, drone and missile attacks, and other attempts to block the strait to commercial shipping, and to comply with UN Security Council resolution 2817.”
Resolution 2817, approved on March 11, condemned Iran’s attacks on its neighbours and called on Tehran to cease hostilities.
The countries said the effects of Iranian actions will be felt in all parts of the world, especially by the most vulnerable people.
“We express our readiness to contribute to appropriate efforts to ensure safe passage through the strait. We welcome the commitment of nations who are engaging in preparatory planning,” they said.
On Thursday, defence secretary John Healey warned that Tehran’s attacks overnight threatened to “further destabilise the region” as he reiterated the government’s call for de-escalation.
Speaking on a visit to Dreghorn Barracks in Edinburgh, Mr Healey added: “We will step up the defensive support that we can offer to those Gulf states.”
Following an Israeli strike on its main natural gas field, Iran hit multiple energy sites across the Gulf, including a Saudi oil refinery, Qatari gas facilities and two more oil refineries in Kuwait.
British forces are already deployed to the Middle East, with RAF jets flying defensive sorties against Iranian drones across the Gulf and British air defence systems protecting critical infrastructure in Saudi Arabia.
UK military planners have also joined the US Central Command to help formulate proposals for opening the Strait of Hormuz, a critical trade route for the world’s oil and gas.
Meanwhile, Sir Keir Starmer chaired a meeting of the government’s emergency Cobra committee on Thursday morning in response to the attacks overnight.
The PM also spoke to French president Emmanuel Macron and Nato secretary-general Mark Rutte, to discuss what he called the “egregious Iranian strikes” as well as the formulation of a “viable plan” to reopen the Strait of Hormuz.
