Brent oil dived to a four-year low point today, extending this week's sharp falls on global economic fears and plentiful crude supplies.
Brent North Sea crude for delivery in November tumbled to $88.11 a barrel, touching the lowest level since December 1, 2010.
US benchmark West Texas Intermediate (WTI) for November delivery sank to $83.59, a point last witnessed on July 3, 2012.
Brent later stood at $89.47 in London deals, down 58 cents from yesterday's closing level. WTI changed hands at $84.54, down $1.23.
Both contracts have now plunged by about a fifth in value since striking their 2014 peaks in June.
Crude futures tumbled yesterday as fresh evidence of economic weakness in the euro zone, especially in Germany, added to concerns slowing global growth and abundant oil supplies.
The market accelerated its losses after the head of the International Monetary Fund warned the euro zone could slip back into recession.
Today's losses come as equities markets suffer another heavy sell-off. Europe's main stock markets fell heavily, hit by growing signs that the euro zone economy may be at risk from recession and by gloom over the global outlook.
Sentiment was also hut by stubborn worries over the Ebola outbreak in West Africa.
A fresh round of negative euro zone data published yesterday showed a 5.8% slump in German exports in August, while leading think tanks also slashed their growth forecasts for Europe's largest economy.
IMF chief Christine Lagarde has also warned there was a 35-40% chance of the euro zone slipping back into recession if action is not taken to prevent it. The forecast came after the IMF had this week cut its estimates for global economic growth for this year and in 2015.
Oil prices have been dampened also by ample global supplies owing to increased US shale gas production and a return to the market of Libyan oil following a prolonged disruption due to civil unrest.
In the US this week, a closely monitored report showed rising crude inventories, signalling weakening demand in the world's top oil consuming nation.
The Department of Energy said US crude reserves leaped by 5 million barrels in the week ending October 3, more than double analysts' consensus forecast.