Miners led the FTSE 100's biggest fallers in morning trading after a sudden collapse in copper prices knocked oil off the top of the commodities watch list.
The metal plunged by more than six per cent after the World Bank slashed its global growth forecast for 2015.
Antofagasta was the biggest faller, with shares dropping more than nine per cent to 644p in mid-morning trading, while Glencore also fell nine per cent to 244p and Anglo American dropped 8.2 per cent to 1,051p.
In a statement released overnight, the World Bank warned the US alone cannot drive global recovery, cutting its forecast for world economic growth for this year to three per cent, from 3.4 per cent in June. It also cut its forecast for next year, from 3.5 per cent to 3.3 per cent.
It also slashed its forecast for Eurozone growth in 2015 to an anaemic 1.1 per cent, rising to 1.6 per cent in 2016.
The organisation added that oil prices, which have plummeted more than 57 per cent since June, are likely to "lower inflation worldwide and [are] likely to delay interest rate hikes in rich countries".