London open: Early gains for blue chips

London has pushed on again in early dealings with miners leading the way and a mixed morning so far for retailers.Supermarket giant J Sainsbury had its best Christmas ever, with better than expected sales, a growing market share and a record number of customers despite the snow. Like for like sales excluding fuel rose 3.6% in the 14 weeks to 8 January, or 5.4% including petrol, while total sales grew 6% and 7.5% respectively. Shares in the supermarekt giant are down, though, with Marks & Spencer also under pressure.Miners are the main driver for the index so far today, with good gains for Kazakhmys, ENRC and Vedanta.Life groups are also seeing some buyers, with Prudential, Old Mutual and Legal & General all going well.That could be the result of the end of fund manager Gartmore Group's ill-starred and brief stint as a publicly listed company. The company's board has agreed to a £335.3m takeover by rival Henderson Group in a deal that values each Gartmore share at 92.1p.Centrica's appeal to have competition restrictions lifted from its Rough gas storage facility in the North Sea has been rejected by the Competition Commission.Quality and safety services provider Intertek has paid $6.9m for American Analytical Chemistry Laboratories (AAC Labs), a business that provides laboratory-based food testing in the United States.Conveyor belt maker Fenner has seen a sharp increase in first quarter profitability compared to the same period last year. On the retail front, trendy fashion retailer SuperGroup predicts top-end profits following its best ever Christmas, almost doubling retail sales during the nine weeks to 2 January. Bakery chain Greggs like-for-like sales rose 0.6% over the Christmas trading period while total sales climbed 3.5% as shoppers snapped up hot coffee and mince pies. Mail order was a tough business when the snow hit in December, but N Brown struggled through to lift like-for-like sales by 1.2%. "The extreme weather conditions eventually affected customers who were concerned whether their Christmas orders would be delivered on time," it said.Restaurant Group, which owns the Garfunkel's, Chiquito and Frankie and Benny's chains, expects full-year profits to be "just ahead" of the market consensus.