UK Stocks-Factors to watch on May 19

May 19 (Reuters) - Britain's FTSE 100 index is seen opening down 60 points, or nearly 1 percent, on Thursday, according to financial bookmakers. For more on the factors affecting European stocks, please click on * The UK blue chip index on Wednesday ended flat in percentage terms at its close at 6,165.80 points, as luxury goods firm Burberry fell after a slump in its profits and miners tracked weaker metals prices. * ANTOFAGASTA: Antofagasta said on Wednesday it had signed an acco