Oil importing countries should implement emergency oil-saving policies if supplies fall by as little as 1m-2m barrels a day, the International Energy Agency will warn next month.

The figure is much lower than the official trigger of 7 per cent of global oil supply - equivalent to 6m b/d - agreed in the treaty that founded the energy watchdog for industrialised countries after the oil crisis of the 1970s. A fall in supply of just 1m-2m b/d would be equivalent to the disruptions during the 2003 Iraq war or the 2002 oil industry strike in Venezuela.