Sir Keir Starmer, the Labour leader, said: “We condemn the Iranian regime’s decision to subject Israelis to these unacceptable attacks.

“The international community has been united in urging restraint and we regret that yet again Iran has chosen a different, dangerous path.”

The attack was first considered “imminent” by US intelligence on Wednesday, after Ali Khamenei, Iran’s supreme leader, said Israel “must be punished” for a strike on an Iranian consulate compound in Damascus on April 1.

The strike killed 13 including a senior IRGC general, six other Iranian officials and six Syrians.

Iran’s response is thought to be directed at government and military buildings in Israel, not civilian targets. It is the first time that Iranian forces have directly attacked Israel, although Iran has backed the proxy groups Hamas and Hezbollah in Gaza and Lebanon.

Israel has indicated that it will strike Iran directly in response to any attack on its territory.

Iran’s most notorious drone is the Shahed, which has been deployed by Russia against Ukraine and by Houthi rebels in Yemen.