Troops are being deployed to Cyprus after ministers activated the first phase of plans to evacuate thousands of Britons from war-torn Lebanon.

Around 700 soldiers will be sent to the Mediterranean island, the Government announced on Tuesday night, with the Middle East on the brink of a major war.

The decision came after John Healey, the Defence Secretary, left Labour’s conference in Liverpool to chair a meeting of the Cobra committee.

On Tuesday night, Downing Street urged more than 10,000 UK nationals that are still believed to be in Lebanon to leave the country immediately on commercial flights.

Mr Healey said: “Events in the past hours and days have demonstrated how volatile this situation is, which is why our message is clear, British nationals should leave now.

“We continue to urge all sides to step back from conflict to prevent further tragic loss of life. Our government is ensuring all preparations are in place to support British Nationals should the situation deteriorate.

“I want to thank the British personnel who are deploying in the region for their commitment and professionalism.”

His warning comes after Israel intensified its bombing of Hezbollah strongholds in Lebanon.

Security chiefs met in Whitehall on Tuesday afternoon to discuss the Government’s plans should the situation escalate into a full-scale war.

Their conversations were expected to include how thousands of British nationals could be evacuated in such a scenario.

Israel’s military chief has vowed that his country will not stop the bombing after hundreds were killed in two days of attacks on Hezbollah strongholds.

At least 558 people have been reportedly killed in Israel’s “Operation Northern Arrows”, with Monday being the deadliest day for Lebanon since the 2006 Israel-Hezbollah war.

British officials have drawn up detailed plans for a potential evacuation operation but have warned that it would be fraught with difficulty.

They have been urging any UK nationals who are still in the country to leave on commercial airlines whilst flights are still operating in and out.

There were thought to be up to 15,000 passport holders in the nation last month as hostilities between Hezbollah and Israel intensified.

Ministers have been warned by officials that efforts to evacuate them should a full-blown war break out would be severely restricted.

Israel would likely take out Beirut airport – which is the only major passenger hub in Lebanon – within the first few hours of hostilities.

That would make the kind of airlifts that the RAF used to evacuate evacuate a similar number of nationals from Kabul three years ago virtually impossible.

Ministers are determined to avoid being caught unprepared as Britain was in 2021. A small number of military personnel are in Lebanon and will lead the operation if the conflict escalates.

Defence sources do not think an evacuation will be necessary this week but recognise that the situation could quickly deteriorate.

Speaking at the UN in his final speech to it as US president, Joe Biden joined other world leaders in urging restraint.

“A diplomatic solution is still possible,” he said. “Full-scale war is not in anyone’s interest.”

Sir Keir Starmer called on Israel and Lebanon to “pull back from the brink” and for a ceasefire in Gaza in his speech at the Labour conference.

Speaking on the Government plane on Tuesday night, on his way to the UN General Assembly in New York, Sir Keir said: “The most important message from me this evening is to British nationals in Lebanon, to leave immediately and I just want to reinforce that.

“Yes, we are ramping up the contingency plans, I think that you would expect that in light of the escalation.

“But it is important that we be really, really clear - now is the time to leave.

“More broadly, I am worried about the situation and I think we need to be clear [that] we need de-escalation, we need a ceasefire, we need to pull back from the brink.

“I think that will be amongst the first topics we discuss in New York.”

At the UN assembly, Recep Tayyip Erdoğan, Turkey’s president, compared Benjamin Netanyahu, Israel’s prime minister, to Adolf Hitler and called for him to be stopped by “an alliance of humanity”.

But, from Israel, Mr Netanyahu repeated his warning to Lebanese citizens to evacuate areas where rockets were hidden and warned that Hezbollah was “leading them to the brink”.

The IDF confirmed that it targeted and killed Ibrahim Qubaisi, the commander of Hezbollah’s missiles and rockets force, in the airstrikes.

Lt Gen Herzi Halevi, the Israel Defence Forces’ chief of staff, said the strikes will continue “intensely” until Hezbollah stopped firing rockets across the border.

“We are now winning on every front. We have killed roughly 20,000 Hamas terrorists in Gaza,” an Israeli official told the Telegraph, “and we still have a lot more to show if needed”.

Some 300 rockets were fired from Lebanon at northern Israel on Tuesday, the IDF said.

Lebanon’s emergency committee said 252 schools had been turned into shelters for 27,000 people who have fled the south amid Israel’s bombardment.

Ayatollah Ali Khamenei, Iran’s Supreme Leader, is set to speak on Wednesday. Iran is a major backer of Hezbollah.