By Sara Sjolin, MarketWatch

LONDON (MarketWatch) -- U.K. stocks declined for a third straight day on Thursday, led by banks and resource firms amid worries over a potential reduction in U.S. bond buys.

The FTSE 100 index slid 1% to 6,445.25, closing at the lowest level since Oct. 10.

Shares of Sports Direct International PLC posted the biggest loss in the index, sliding 13%, after the company said Group Finance Director Bob Mellors will retire at the end of the month on health grounds.

Oil-services firms were also lower, hurt by a profit warning from John Wood Group PLC , which downgraded expectations for its engineering division. John Wood stumbled 9.9% outside the main index.

Within in the FTSE 100, Petrofac Ltd. dropped 4% and AMEC PLC gave up 5%.

The broader market continued to slide on fears the U.S. Federal Reserve could taper its $85-billion-a-month bond buys at its meeting next week. Recent upbeat data and a budget deal in Washington have added to speculations the central bank could start cutting its asset purchases at the December meeting. Data out on Thursday were mixed, however. Follow the U.S. stock-market action here.

Banks, which are among the most risk-sensitive sectors, fell. Shares of Royal Bank of Scotland Group PLC (RBS) gave up 2.8%, Barclays PLC (BCS) fell 2.2% and heavyweight HSBC Holdings PLC (HSBC) shaved off 0.4%.

Resource firms were also gave up ground. In the energy sector, BG Group PLC lost 1.3% and BP PLC (BP) erased 1.4%. Oil prices were higher.

Among miners, Fresnillo PLC fell 5.2%, Randgold Resources Ltd. dropped 3.8% and BHP Billiton PLC (BHP) eased 1.7%. Metals posted sharp losses.

Shares of Anglo American PLC lost 1.4% as the miner said it expects to face headwinds next year.

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