The drop brings the price into the lower end of OPEC’s preferred price band of $22-28 a barrel. However, the organisation insists that quota discipline is not yet a major problem.

‘The organisation has a mechanism to control compliance with quotas,’ said secretary-general Alvaro Silva at the Oil & Money conference in London on 5 November. ‘Compliance is not a problem at the moment – prices are in the band.’

For the next few months that may be true, as oil demand enters a seasonal upturn. But in the second quarter of next year, as the warmer northern hemisphere spring reduces the need for heating fuel, demand and prices could fall.

Data released by the US government’s Energy Information Administration on 6 November showed a rise in crude oil stocks of 3.4 million barrels but drawdowns for stocks of derivatives like gasoline, distillate and heating fuel. The figures suggest that demand is picking up as winter approaches, and that the supply chains are recovering from the damage sustained by heavy storms in the Mexican Gulf in September and October.