The dollar surged to a two-year high against the pound and a six-month peak against the euro on Friday, as fears about spreading economic gloom triggered a sell-off in commodities.

Against sterling, the US currency notched up its 11th consecutive day of gains – its longest uninterrupted rise in more than 35 years – as markets became increasingly convinced that the US was best-placed to weather the global downturn.

The Reuters-Jefferies CRB index, a benchmark for commodities, fell more than 2.5 per cent to its lowest level since late March. The index has fallen almost 20 per cent since an all-time high in July, but is still 22 per cent higher than a year ago.