UK forces were involved in supporting Israel in the conflict in the Middle East after Iran launched a missile attack on the country.
Defence Secretary John Healey, who is Cyprus to visit personnel based on the island, said British forces had “played their part in attempts to prevent further escalation”, without giving more details.
The BBC understands UK fighter jets were involved, as they were in April when Iran last attacked Israel with missiles.
Responding on Tuesday to Iran’s attack, Prime Minister Sir Keir Starmer said the UK “stands with Israel” and recognises its right to self-defence.
Iran’s Islamic Revolutionary Guard Corps said it had launched the missiles in retaliation for recent attacks that killed the leaders of the Hezbollah and Hamas militant groups, as well as a senior Iranian commander.
Israel said most of the 180 missiles fired were intercepted.
Healey thanked British personnel involved for their courage and professionalism.
“The UK stands fully behind Israel’s right to defend its country and its people against threats.”
Healey’s visit to Cyprus will see him meet some of the British personnel preparing for the possibility of evacuating British nationals from Lebanon.
Britons in Lebanon have been advised to register their presence with officials on the government’s website and a UK-chartered plane is set to leave Beirut on Wednesday.
But some told the BBC they had received no confirmation or details about their booking on the government-chartered flight, despite paying for a seat.
British citizen Libby, 25, was about to board a commercial flight from Beirut to Cairo on Wednesday morning, and described the situation in the Lebanese capital as “terrifying”.
“You can’t sleep because you can hear the Israeli drones over your head, you wake up in the night because you hear strikes,” she told the BBC Radio 4’s Today programme.
In April British jets shot down a number of drones fired at Israel from Iran.
The drones were intercepted by the RAF in Syrian and Iraqi airspace, where it was already operating as part of the Operation Shader mission against the Islamic State group.
The decision to use jets in April was taken by the previous Conservative government and supported at the time and since by Sir Keir.
Sir Keir used the address from Downing Street to condemn Iran’s attack on Israel, saying he was “deeply concerned that the region is on the brink”.
“We stand with Israel and we recognise her right to self-defence in the face of this aggression,” he said.
Calling on Iran to stop its attacks, he added: “Together with its proxies like Hezbollah, Iran has menaced the Middle East for far too long, chaos and destruction brought not just to Israel, but to the people they live amongst in Lebanon and beyond.
“Make no mistake, Britain stands full square against such violence. We support Israel’s reasonable demand for the security of its people.”
Sir Keir was on the phone to his Israeli counterpart Benjamin Netanyahu when the Iranian attacks began.
The two men had been speaking for around 15 minutes – about the prospect of missiles being fired by Tehran – when Netanyahu had to abandon the call because he had been told the attacks were under way.
During their call, Sir Keir also underlined the importance of a ceasefire in Lebanon and Gaza.
Conservative Party leader Rishi Sunak said: “We stand unequivocally by Israel’s right to defend itself including against Hezbollah in Lebanon.”
