Sir Keir Starmer will chair a meeting of the emergency Cobra committee on Wednesday to discuss the security situation in the Middle East, amid fears that the US will join Israel's attack on Iran.
The Prime Minister is expected to gather experts after returning from the G7 summit in Canada, where he met Donald Trump.
It comes after US officials indicated that Iran has 24 to 48 hours to surrender and save itself from American invention as President Trump considers joining Israel's war.
White House officials said the next two days will be critical in determining whether a diplomatic solution can be found to the burgeoning crisis in the Middle East.
The families of British diplomatic staff in Israel have been 'temporarily withdrawn' as Tel Aviv and Tehran continue to exchange fire.
