UPDATE 1-UK Stocks-Factors to watch on Aug. 10

Britain's FTSE 100 index is seen opening down 4 points at 7,738 on Friday, according to financial bookmakers, with futures down 0.4 percent ahead of the cash market open. * NATIONWIDE BUILDING SOCIETY: Britain's Nationwide Building Society said on Friday its pre-tax profit fell by 13 percent in the first quarter as intense competition continued to dent its performance. * BHP: Mining heavywei