Energy analysts modelling a war involving Iran have long feared two developments: the Islamic Republic lashing out at its oil-rich neighbours and

a blockade of the Strait of Hormuz

, through which a third of global seaborne crude and a fifth of liquefied natural gas (LNG) transit daily. Until Feb 28, both eventualities seemed remote, because Iran had too much to lose. It would risk pushing Gulf states towards America, its sworn enemy; angering China, the main buyer of its oil; and inviting strikes on its own petroleum infrastructure.