Oil prices have fallen 30% since June, due to slow growth in emerging nations and concerns over Japan and eurozone
Figures indicating a sharp slowdown in Chinas industrial production pushed Brent crude oil below $80 (£51) a barrel on Thursday, after three days of falling prices that took the cost of a barrel to a four-year low.
The further slackening of activity in China the worlds biggest energy consumer has also forced down the price of industrial metals and revived fears of a broader faltering of the worlds economic recovery after the 2008 crash.