FTSE hits one-week low as slump in copper clobbers miners

* Mining index (Jakarta: ^JKMING - news) dives 6.2 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 fell more than 2 percent on Wednesday, with a plunge in metals prices due to global growth concerns prompting jittery investors to exit mining stocks.

The UK mining index dropped 6.2 percent, the biggest one-day percentage fall in three years, after copper plunged 8 percent at one point to its lowest in 5-1/2 years, triggered by a wave of stop-loss selling following a downward revision to global growth by the World Bank.

Late on Tuesday, the bank lowered its global growth forecast for 2015 and next year due to disappointing economic prospects in the euro zone, Japan and some major emerging economies, which 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," David Battersby, investment manager at Redmayne-Bentley, said.

"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 3.9 to 8.6 percent. Glencore (Xetra: A1JAGV - news) slumped 9.4 percent, also hit by Citigroup (NYSE: C - news) cutting its target price for the stock.

Miners dragged down the blue-chip FTSE 100 index, which was 2.1 percent lower at 6,407.01 points by 1556 GMT after touching a one-week low of 6,353.65 at one point.

Some analysts, however, saw bargains in mining stocks.

"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 at the start of September, its highest since early 2000, but it then slumped to 15-month lows in October on weak European economic data.

Among other movers, Standard Chartered Bank fell 5.4 percent on concerns about the Asia-focused bank's large exposure to the commodities markets and as UBS (NYSEArca: FBGX - news) cut its stance on the stock to "neutral" from " buy", traders said.

UK's biggest retailer Tesco (Xetra: 852647 - news) rose 1.7 percent, the top gainer in the FTSE 100 index, as Exane upgraded the stock to "outperform" from "neutral" saying nearer-term catalysts existed, and as a media report said Billionaire Bill Ackman considered investing in the company, traders said.

Mid-cap oil producer Premier Oil fell 3.7 percent after saying it expected to book a $300 million impairment charge due to the plunge in oil prices and planned to cut jobs and investment to rein in costs. (Additional reporting by Sudip Kar-Gupta; Editing by Alison Williams)