London looks set to take its lead from Wall Street, which saw a shake out yesterday, and open lower, though there is some cheer in the form of better than expected sales figures from the bellwether of the High Street, Marks & Spencer.Traders expect the FTSE 100 will open around 30 points easier.Marks & Spencer enjoyed a strong start to the year with food and non-food like-for-like sales beating expectations in the first quarter. Total sales in the 13 weeks to March 27 were up by 6.2% from the same period the previous year and by 5.1% on a like-for-like basis.Vedanta Resources saw a significant uplift in annual production at all its businesses in fiscal 2009/10, with record quarterly production of iron ore and aluminium during the first three months of 2010.Oil and gas firm BG Group and its joint venture partners have successfully completed drilling a Tupi field appraisal well in the BM-S-11 licence area, Santos Basin pre-salt, offshore Brazil. The appraisal well confirmed the presence of hydrocarbons on the outer limits of the Tupi field.Switching to the airways, British Airways and Spanish airline Iberia have formally signed a merger agreement that will result in the creation of one of the world's largest airline groups by the end of the year, BA said, while no-frills airline Easyjet said it carried 13.5% more passengers in March compared with the same month in 2009.