The economic downturn is drying up demand for oil and natural gas, dropping the benchmark price for a barrel of oil to below $50.

Indeed, several refineries in Japan have stopped operations, but crude prices have tumbled below $100 a barrel for the first time in more than a week.

In Europe, taxes account for up to four-fifths of the retail price, so even quite big changes in the price of crude have a more muted effect on pump prices than in the past.