Thousands of UK nationals risk “becoming trapped in a warzone” if they fail to leave Lebanon, the Foreign Secretary has warned.

Speaking at the House of Commons despatch box on Tuesday, David Lammy issued a one-word message to British nationals in the Levantine nation: “Leave.”

He confirmed Prime Minister Sir Keir Starmer had chaired a Cobra emergency meeting on Tuesday amid tensions in the Middle East.

The meeting followed a rocket strike which killed 12 young people on a football field in the mainly Druze town of Majdal Shams.

Israel has said the Iranian-backed Hezbollah was responsible for the attack on Saturday evening, but Hezbollah denied a role in the strike.

Israel’s prime minister, Benjamin Netanyahu, vowed retaliation against the group when he wrote on X, formerly Twitter: “Our response will come, and it will be severe.”

Mr Lammy told MPs: “On July 27, Hezbollah launched a series of rockets into northern Israel and the occupied Golan Heights.

“Tragically in Majdal Shams, one strike killed at least 12 civilians, young people, one just 10 years old, who were playing football.

Israeli Prime Minister Benjamin Netanyahu has threatened a ‘severe’ response for the Golan Heights rocket attack (Stefan Rousseau/PA)

“I extend my deepest sympathies to their families and to the Druze community as they grieve for their loved ones.

“The Government is unequivocal in condemning this horrific attack and calling on Hezbollah to cease their rocket strikes. This atrocity is a consequence of indiscriminate firing, paying no heed at all to civilian life.

“This attack is part of an intensifying pattern of fighting around the Israeli-Lebanese border. For months now, we’ve been teetering on the brink.

“The risk of further escalation and regional destabilisation is now more acute than ever.”

Mr Lammy said he had spoken to the Lebanese prime minister, Najib Mikati, in his first week in office, and again on Monday, to express his “concern”, and had previously met with Mr Netanyahu.

Turning to UK nationals in Lebanon, Mr Lammy said: “The Prime Minister chaired a Cobra meeting this morning and I’m working with Foreign Office consular teams to make sure we are prepared for all scenarios, but if this conflict escalates, the Government cannot guarantee we’ll be able to evacuate everyone immediately.

“People may be forced to shelter in place and history teaches us that in a crisis like this one, it is far safer to leave while commercial flights are still running rather than running the risk of becoming trapped in a warzone.

“My message, then, to British nationals in Lebanon is therefore quite simple: leave.”