UK Stocks-Factors to watch on Oct. 21

Oct 21 (Reuters) - Britain's FTSE 100 index is seen down 8 points, or 0.1 percent, on Friday, according to financial bookmakers. * The UK blue chip index closed up 4.98 points, or 0.1 percent, on Thursday at 7,026.90. Banks helped to support British blue-chips, buoyed by good performance from U.S. lenders in key business areas on a volatile day as the European Central Bank held policy steady. * BHP: BHP Billiton, Chairman Jac Nasser, one of the most powerful figures in the minin