The S-300’s surface-to-air rockets can hit many targets at once, including in-coming cruise missiles, making any Western or Israeli strike on Iran much more difficult.

News of the multi-billion pound deal with Moscow has caused fury and fear among Western powers as they desperately try to stop the country developing nuclear weapons.

An intelligence source told The Mirror: “In the game of bluff and counter-bluff this is bad news for Israel and the West.