Sir Keir Starmer welcomed the US-Iran peace deal as a “hugely important step forward in ending the war” as he stressed that the Strait of Hormuz must remain “fully and permanently open”.
The Prime Minister congratulated Donald Trump and key mediators on the “breakthrough” after the US president said an agreement “is now complete” and the Strait of Hormuz oil and gas shipping route is to be reopened without tolls.
Sir Keir said in a statement: “I warmly welcome today’s agreement reached between the United States and Iran.
“This is a hugely important step forward in ending the war, ensuring regional stability, and re-opening the Strait of Hormuz.”
He continued: “Attention must now turn to fully implementing the memorandum of understanding to ensure the Strait reopens and remains fully and permanently open, and that the detailed elements of the nuclear agreement are finalised. We stand ready to support the technical talks that will now begin. Our priority is that this becomes a durable and lasting peace, and we will work with international partners to support that.
“We are clear that toll-free freedom of navigation must now be restored in the Strait of Hormuz, to begin easing the severe economic impacts that have been felt for several months – on families here in the UK and around the world.”
Sir Keir said the UK would stand up the defensive mission led by Britain and France to assist with demining the Strait of Hormuz once the conflict is paused.
“For any peace to endure, it is essential that the commitments made, particularly in relation to Iran’s nuclear programme, are robust, verifiable, and fully implemented. It remains the UK’s firm and longstanding position that Iran must never have a nuclear weapon.”
In a joint statement with the leaders of France, Germany and Italy, Sir Keir also said: “We are prepared to lift relevant sanctions in response to clear, verifiable steps by Iran on its nuclear programme.”
The so-called E4 also underlined the importance of “unconditional and unrestricted freedom of navigation” in the strait, and called for the accord to be “implemented rapidly and comprehensively”.
Mr Trump earlier said a deal had been reached and that he was authorising an end to the US naval blockade of Iranian ports in the Strait of Hormuz.
The American leader, who is celebrating his 80th birthday, wrote on his Truth Social platform on Sunday: “The Deal with the Islamic Republic of Iran is now complete.
“Congratulations to all!
“I hereby fully authorize the toll free opening of the Strait of Hormuz, and, simultaneously herewith, authorize the immediate removal of the United States Naval blockade.
“Ships of the World, start your engines. Let the oil flow!”
Shehbaz Sharif, the prime minister of Pakistan, which has been mediating in the conflict, said the accord covered Lebanon.
He wrote on X: “Following intensive talks, we are pleased to announce that the Peace Deal between the United States of America and Islamic Republic of Iran has been REACHED. Both sides have declared the immediate and permanent termination of military operations on all fronts, including in Lebanon.
“The official signing ceremony will be on Friday, 19 June in Switzerland.”
He added that “mediators will facilitate a series of meetings this week”.
“These pre-implementation discussions will lay the foundation for the technical talks and the official signing ceremony.”
Full details of the deal did not immediately emerge and it was unclear how soon the Strait of Hormuz could reopen to all vessels.
Central to the negotiations has been Iran’s stranglehold on the critical waterway, which has disrupted global oil and gas supplies and driven up fuel and food prices.
Another flashpoint has been Tehran’s nuclear plans, which it insists are peaceful but the US and Israel fear could be used to build a weapon due to its stockpile of highly enriched uranium.
The US president is expected to discuss plans with allies during next week’s G7 summit in France.
Foreign Secretary Yvette Cooper said the UK stands “ready to help” develop the US-Iran agreement into “a lasting peace”.
She said: “I strongly welcome the announcement of an agreement between the US and Iran.
“It is vital that toll-free freedom of navigation through the Strait of Hormuz is swiftly restored, so international shipping can get moving again to help the global economy and families here at home.
“The UK stands ready with France and other countries to support that process as needed.
“Our longstanding position is that Iran must never be allowed to develop a nuclear weapon. The UK is ready to support the technical work to ensure that vital objective is implemented.
“This agreement is important for regional and global security and for the international economy. Thank you to all those involved in negotiations including Pakistan and Qatar. It is vital that progress continues – we stand ready to help make it a lasting peace.”
