Crude oil prices sank below the $42 a barrel level, a near-four year low, as commodity markets marked a new stage in their retreat, with US petrol prices falling below the $1 a gallon mark and copper dropping to the $3,000 a tonne level.

The huge fall in US employment in November, announced, underlined fears that the world’s biggest economy was heading for a deep recession and prompted renewed selling pressure across commodity markets. Nymex January West Texas Intermediate fell $2.86 to a low of $40.81 a barrel, its lowest level since January 2005, down 25.02 per cent this week.