PA MediaSir Keir Starmer has called on Iran to “return to the negotiating table” after the US bombed nuclear sites in the country overnight.
In a statement, the UK prime minister said stability in the region was a priority, describing Iran’s nuclear programme as “a grave threat to international security”.
The BBC understands there was no UK involvement in the US strikes on Iranian nuclear facilities and that the prime minister was informed of them in advance.
The US said it had carried out strikes on three nuclear facilities in Iran: Natanz, Isfahan and Fordo on Saturday night.
Business Secretary Jonathan Reynolds told BBC’s Sunday with Laura Kuenssberg the UK’s position was to advocate for “calm and de-escalation”.
“We support and always have done the prevention of the Iranian regime obtaining nuclear weapons.
“We hoped and proposed a peaceful, diplomatic means to do that – it was the Iranians who were not willing to go along with that.”
Iran has said its nuclear ambitions are peaceful.
Israeli President Isaac Herzog told the same programme that Iran’s nuclear programme had been hit “substantially” but added that he did not yet know the exact details of what happened overnight.
“[The US attacks] come in addition to the Israeli strikes throughout the week which were vital and important in respect to this threat [from Iran],” he said.
The strikes followed the launch of a new Israeli operation against Iran overnight into 13 June. Israel said its targets were military sites, including nuclear facilities.
Iran launched retaliatory strikes – with the two countries continuing to exchange fire since.
President Donald Trump had initially refused to say whether the US would get involved, with the White House saying on Friday that a decision would be made “within the next two weeks”.
In a televised address following the strikes, the president said the operation was a “spectacular military success”, adding that if Iran did not make peace quickly it would face “far greater” attacks.
Iran’s ambassador to the UK, Seyed Ali Mousavi, told the BBC that Iran is considering the “quantity and quality” of its reaction with regards to retaliation.
No increase in off-site radiation has been reported, according to the UN’s International Atomic Energy Agency (IAEA) latest update.
Iran’s foreign minister Seyed Abbas Araghchi called the US strikes “outrageous” and said they would have “everlasting consequences”.
“Each and every member of the UN must be alarmed over this extremely dangerous, lawless and criminal behavior,” he added.
UN Secretary General António Guterres said the overnight strikes were a “dangerous escalation”.
Reacting to the US action overnight, Conservative leader Kemi Badenoch, said: “By targeting Iran’s nuclear sites, the US has taken decisive action against a regime that fuels global terror and directly threatens the UK.”
Starmer has previously urged for further negotiations in a bid to de-escalate the conflict.
“The risk of escalation in the region is obvious,” he said at the time.
Foreign Secretary David Lammy travelled to Washington last week to meet Secretary of State Marco Rubio and US special envoy Steve Witkoff.
The foreign secretary said after the meeting: “We discussed how a deal could avoid a deepening conflict. A window now exists within the next two weeks to achieve a diplomatic solution.”
He formed part of a European contingent which met with Iranian officials on Friday.
The Foreign, Commonwealth and Development Office (FCDO) has advised against all travel to Israel and the Occupied Palestinian Territories and Iran.
