Copper extended its extraordinary run to a fresh record high on Friday on news of a further decline in the inventories of the metal, which are critically low levels. Copper has risen more than 70 per cent so far this year, and is now near record highs in inflation-adjusted terms that were set in the mid-1960s.

The three-month copper price struck a fresh high of $7,780 a tonne on the London Metal Exchange, before easing to $7,647 in late trade, or about $15 above the previous close and up more than nine per cent on the week.