Iran was once one of the key oil suppliers to the world. No longer. Constrained by decades of sanctions, Iranian oil exports now amount to less than 2 per cent of global supplies, with most of those barrels going to China at discounted prices.

As "Hvylya" reports, in a Financial Times analysis, energy historian Daniel Yergin traced the roots of the current crisis back to "strikes by oil workers in Iran in the autumn of 1978" - part of the protests that toppled the Shah and ushered in the Islamic Republic. The disruption of oil from one of the world's major suppliers set off panic in global markets and established the enduring fear of Gulf energy being cut off by war.

Iran is not the only former oil giant to fall. Venezuela, once "a star of world oil and one of the founding members of Opec," can today hardly be called a petrostate, Yergin wrote. It produces less oil than the US state of North Dakota and a quarter as much as neighbouring Brazil.

The irony is sharp: the country whose revolution created the nightmare scenario for global energy is now too marginal as a producer for its own oil to matter much. But its ability to disrupt the Strait of Hormuz - through which 20 per cent of the world's oil and nearly 20 per cent of global LNG flow - means Iran can still hold energy markets hostage without exporting a single barrel.

That, Yergin argued, is the real threat. Not Iranian oil, but Iranian geography. The strait remains "one of the globe's central maritime chokepoints," and Tehran has done everything it can since the war began to weaponise that position.

Also read: Not Democracy: Foreign Affairs Analyst Reveals the Most Likely Outcome of Iran's Power Vacuum