As Russia’s military vice closes on Ukraine, the west has countered with giant economic pincers. The US has proposed an import ban on Russia’s crude and refined oil products. Nearly half of that country’s oil production of 11mn barrels a day are exports, about 5 per cent of world output. How could the US-led coalition of sanctions allies cover the supply shortfall if the embargo goes ahead?

Brent prices reflected the scale of challenge, spiking at almost $140 a barrel, before settling at $125 at noon in London. Massive disruption may lie ahead. Oil still provides almost a third of the world’s primary energy supply, according to BP data.

The proposed embargo revives memories of the oil shock of the 1970s. It makes the most recent big threat to supply — a 2019 drone attack on Saudi Arabia’s main refinery — pale into insignificance.