RSA a faller as Britain's FTSE dips

* FTSE 100 down 0.3 pct

* Old Mutual (Other OTC: ODMTY - news) gains on strong results

* BP, Anglo American (LSE: AAL.L - news) trade ex-dividend

By Liisa Tuhkanen

LONDON, Aug 6 (Reuters) - Britain's top share index edged lower on Thursday, with insurer RSA a faller after weak results from a potential bidder reduced prospects of a takeover.

RSA, the subject of interest from Swiss rival Zurich Insurance, dropped 1.5 percent.

"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 the top blue chip riser, up 2.7 percent after strong results.

Aviva (Other OTC: AIVAF - news) also benefited from well-received results, adding 1.2 percent after posting forecast-beating half-year operating profit, boosted by the ahead-of-schedule integration of recent purchase Friends Life (Other OTC: RSLLF - news) .

The blue-chip FTSE 100 index was down 0.3 percent at 6,732.50 points by 0835 GMT. It gained 1 percent in the previous session, boosted by better-than-expected results and a rebound in the mining sector.

BP and Anglo American contributed to Thursday's falls as they traded without the attraction of their latest dividend payouts.

BP was the faller, down 3 percent, while Anglo American shed 2.6 percent. The two combined to take nearly 10 points off the index.

Also in focus for equity investors, the Bank of England is releasing a slew of data at 1100 GMT, and is likely to reveal its policymakers have split over interest rates, adding to expectations that the central bank is heading for its first increase in borrowing costs in nearly a decade. (Reporting by Liisa Tuhkanen, editing by John Stonestreet)