A blockade of the strait, through which one-fifth of global oil consumption passes, would have a catastrophic impact on the world economy. Iran, which depends on its oil revenues, has much to lose, as does China, its main customer.

About a quarter of all global oil flows through the Strait of Hormuz, the only sea passage from the Gulf to the oceans

As the US joins Israel’s war with Iran, Tehran threatens to block strategic waterway – risking global energy and trade crisis.