FTSE ends sharply lower as slump in copper clobbers miners

* Blue-chip FTSE 100 index closes 2.4 percent lower

* Mining index (Jakarta: ^JKMING - news) dives more than 6 pct as metals prices plunge

* World Bank cut to global growth forecast hits markets

* Premier Oil (LSE: PMO.L - news) slumps as expects $300 mln impairment charge

By Atul Prakash

LONDON, Jan 14 (Reuters) - Britain's top share index ended more than 2 percent lower on Wednesday, with a plunge in metals prices due to global growth concerns prompting jittery investors to exit mining stocks.

The mining sub-index dropped 6.2 percent, the biggest one-day percentage fall in three years, after copper fell as much as 8 percent to its lowest in 5-1/2 years.

Tuesday's downward revision by the World Bank to its global growth forecasts triggered a wave of stop-loss selling of the metal, which has numerous industrial uses.

The bank said disappointing economic prospects in the euro zone, Japan and some major emerging economies would offset the benefit of lower oil prices.

"It's a straight read-across. Global growth estimates are being revised down and metals prices are slumping, forcing large investors to cut their exposure to the sector," said David Battersby, investment manager at Redmayne-Bentley.

"Mining shares are expected to remain depressed in the near term as sentiment is very bearish."

Commodity majors Rio Tinto (Xetra: 855018 - news) , Anglo American (LSE: AAL.L - news) , BHP Billiton (NYSE: BBL - news) and Antofagasta (Other OTC: ANFGF - news) were down 4 to 9 percent, while Glencore (Xetra: A1JAGV - news) slumped 9.3 percent, also hit by Citigroup (NYSE: C - news) cutting its target price for the stock.

Copper mining represented nearly two-fifths of Glencore's operating profit in the first half of 2014 and about a quarter of Anglo American's profit.

Miners dragged down the blue-chip FTSE 100 index, which closed 2.4 percent lower at 6,388.46 points after touching a one-week low of 6,353.65.

But some analysts saw bargains.

"I think in the near term, the miners are overdone. We have been 'short' of mining stocks, but used today as a chance to buy them back as I expect we will see a pause or a short-term bounce before the selling resumes once again," Central Markets trading analyst Joe Neighbour said.

The FTSE 100 hit a peak of 6,904.86 points in early September, its highest since 2000, but slumped to 15-month lows in October on weak European economic data.

Among other movers, Standard Chartered Bank fell 4.9 percent on concerns about its exposure to commodities markets and after UBS (NYSEArca: FBGX - news) cut its stance on the stock to "neutral" from " buy".

Britain's biggest retailer Tesco (Xetra: 852647 - news) rose 0.9 percent to feature among the FTSE's top gainers as Exane upgraded the stock to "outperform" from "neutral" and on a report that billionaire Bill Ackman considered investing in the company.

Mid-cap oil producer Premier Oil fell 3.4 percent after saying it expected to book a $300 million impairment charge due lower oil prices and planned to cut jobs and investment to rein in costs.

Video games retailer Game Digital (LSE: GMD.L - news) slumped 30 percent as heavy competition over holiday periods led to reduced pricing and bundling of games with consoles, hitting margins. (Additional reporting by Sudip Kar-Gupta; Editing by Catherine Evans)