Update: The FTSE 100 has lurched heavily into the red, dragged down by a major sell-off in the commodities sector as metal prices tumbled.
The UK blue-chip index fell 113 points, or 1.5%, to 7,497, with shares in miners sold off heavily.
Metals came under pressure from renewed strength in the dollar, in which they are priced, which rose to its highest level against a global basket of currencies in more than a year.
Miners littered the bottom of the FTSE 100, with the index's heaviest fallers including:
- Fresnillo (FRES) -8.1% at 893.8p;
- Antofagasta (ANTO) -6.2% at 831.6p;
- Evraz (EVRE) -5.9% at 487.4p;
- Anglo American (AAL) -5.8% at £15.48;
- Glencore (GLEN) -5.7% at 298.4p;
- BHP Billiton (BLT) -5.5% at £16.08;
- Randgold Resources (RRS) -5.4% at £50.16;
- Rio Tinto (RIO) -3.5% at £36.46.
It was a similar story on the FTSE 250, where commodities stocks were down heavily. Kaz Minerals (KAZ) fell 10.5% to 549p, Premier Oil (PMO) was down 8.4% at 108.3p and Ferrexpo (FXPO) dropped 7.7% to 158.7p.
'Trading got real ugly on Wednesday afternoon,' said Connor Campbell, analyst at Spreadex. 'The dollar's latest gains were just too much for commodities... leading the FTSE's index-defining oil and mining sectors to have a mid-week breakdown.'
But the sell-off was not limited to commodities stocks. All but a handful of FTSE 100 stocks traded in the red, as bearishness told hold among investors.
Emerging markets officially entered bear market territory, down 20% from their peak, further souring the mood and knocking the shares of investment trusts focused on that sector.
Metal prices had already been under pressure from news of a sharp slowdown in China's fixed-asset investment growth, which had dragged the price of copper down to 13-month lows this week.
Copper had also taken a knock from news the union for Chile's Escondida mine, the world's largest copper mine, had called off a strike after a renewed contract proposal from BHP Billiton, potentially averting a disruption to supply.
'Copper is widely considered to be a bellwether for the global economy and so a weak price is cause for concern,' said Russ Mould, investment director at AJ Bell.
'Copper was in a falling trend between 2011 and 2016 but has bounced back over the past few years. The latest events put an end to that recovery.'