UK Prime Minister Rishi Sunak called Sunday for "calm heads to prevail" as he confirmed that British fighter jets had shot down Iranian drones during Tehran's unprecedented attack on Israel.
Israel and its allies intercepted almost all of the missiles and drones fired by Iran during its first-ever attack on Israeli territory.
Sunak joined world leaders in urging restraint as Iranian President Ebrahim Raisi warned against any "reckless" Israeli retaliation to the strikes, which marked a major escalation in Middle East tensions.
"If this attack had been successful, the fallout for regional stability would be hard to overstate," Sunak told reporters in Downing Street.
"We stand by the security of Israel and the wider region, which is of course important for our security here at home, and what we now need is for calm heads to prevail.
"We'll be working with our allies to de-escalate the situation and I look forward to speaking to G7 leaders later this afternoon," Sunak added.
He also confirmed reports that Britain had helped Israel and other allies repel the strikes.
Foreign Secretary David Cameron said on social media site X that he had held a call with his Iranian counterpart Hossein Amir-Abdollahian, and "formally condemned in the strongest terms Iran's attack on Israel".
"I made clear that Iran must stop these reckless attacks, de-escalate and release the MSC Aries," he said, referring to the Israeli-linked container ship that was seized on Saturday by the Iranian Revolutionary Guards.
Cameron also summoned the charge d'affaires of the Iranian embassy in London, the foreign ministry said.
"At a time of great tension in the Middle East, (the attack) was a profoundly dangerous and unnecessary escalation by Iran," the ministry statement said.
Defence Minister Grant Shapps said UK warplanes had "intercepted and destroyed multiple one-way attack drones launched by Iran and its proxies".
He said on X that the drones had "posed a threat to civilian lives" and that all British aircraft "returned safely to base".
The defence ministry had said late Saturday that it had sent additional fighter jets and air refuelling tankers to the Middle East in the face of the Iranian threats to Israel.
The planes bolstered an existing British operation in Iraq and Syria against the Islamic State group, the ministry added.
