Britain's FTSE drifts lower, eyes on BoE's "Super Thursday"

* FTSE 100 down 0.3 pct

* Equities under pressure as sterling strengthens

* Miners hit as copper sinks to 6 year low

* RSA falls, with focus on prospect of Zurich bid (Recasts)

By Alistair Smout and Liisa Tuhkanen

LONDON, Aug 6 (Reuters) - Britain's top share index edged lower on Thursday, with sterling strength and weak commodity prices knocking exporters and miners respectively, ahead of a wave of central bank releases.

The blue-chip FTSE 100 index was down 0.3 percent at 6,730.00 points by 0956 GMT.

In what has been dubbed "Super Thursday", the Bank of England will release at 1100 GMT data including its interest rate decision, policymakers' votes and a summary of their debate, and quarterly economic forecasts including inflation.

It is likely to reveal its policymakers have split over interest rates, adding to expectations that the British central bank is heading for its first increase in borrowing costs in nearly a decade.

Sterling climbed ahead of the releases, putting shares, especially of exporting companies, under pressure.

Commodity prices remained weak, with copper hitting a six-year low. Miners fell 2 percent, and analysts said falling metals prices may mean the BoE holds off from raising interest rates for longer.

"While strong growth and a tighter labour market have ... (prompted) speculation on the beginning of rate normalisation still this year, the renewed commodity price fall as well as persistent sterling strength are the wild cards for the BoE to hold policy until next year," said David Meier, senior economist at Julius Baer (Other OTC: JBARF - news) .

Among top fallers, RSA fell 1.7 percent. Although RSA's own pretax profit beat expectations, Swiss rival Zurich Insurance, which is interested in bidding for RSA, said it would not overpay for the British insurer.

"In the short term, we expect RSA to trade based on the probability of a takeover bid, rather than fundamental valuation," Bernstein analysts said in a note.

"Hence, on balance we expect the stock to trade down in the very short term."

Other insurers rose, with Old Mutual (Other OTC: ODMTY - news) up 3 percent after strong results.

Aviva (Other OTC: AIVAF - news) also benefited from well-received earnings, adding 0.9 percent after posting forecast-beating half-year operating profit.

BP and Anglo American (LSE: AAL.L - news) contributed to Thursday's falls as they traded without the attraction of their latest dividend payouts, down 3.1 percent and 3.5 percent respectively. (Editing by Catherine Evans)