London open: Blue chips head lower

London's blue chips have retreated after the surge yesterday with a cautious update from Marks & Spencer dampening the mood.The High Street bellwether reported a 3.6% rise in UK like-for-like sales in the first quarter but is cautious about the outlook for consumer confidence and spending. Like for like sales in general merchandise, which includes clothing, were up 6.0% in the 13 weeks ended 3 July, with like for like sales growth in food of 1.5%.Anglo-Swiss mining titan Xstrata has given the green light to a huge investment in a brownfield expansion to the Tintaya copper mine in southern Peru. The Xstrata board has approved a $1.47bn investment to develop the Antapaccay copper project, located around 10 kilometres from the Tintaya open pit mine which is expected to be exhausted in 2012.Shares in BP continue to rise on talk of Middle East investment and possible capping of the leaking Gulf of Mexico well.Tullow Oil can proceed with the $1.5bn acquisition of a 50% stake in two big oil fields in Uganda from Heritage Oil after the government there gave approval after months of wrangling. Tullow exercised its first refusal rights over blocks 1 and 3A in the Albert Basin in Uganda after Heritage agreed to sell the stakes to Eni of Italy.Aquarius Mining is lower after five people died yesterday at its Marikana platinum mine when a shaft collapsed. Storage firm Big Yellow Group enjoyed a "robust" quarter with a particularly "strong" June. Annualised store revenue, for the 51 wholly owned stores, rose 9% to £59.8m at 30 June 2010. Total store revenue was £14.4m for the quarter, up 10% from the same quarter last year. Private equity leviathan 3i said its investments are stabilising or improving while the pipeline of investment opportunities looks promising. Investment in the second quarter of 2010 totalled £105m, compared to £79m in the second quarter of 2009. Enterprise software giant Autonomy has licensed its Intelligent Data Operating Layer (IDOL) software to Kraft Foods, the US processed foods giant which last year bought up UK confectionery firm Cadbury. Financial details of the deal were not disclosed.South African bank Investec has received a number of approaches from parties interested in acquiring its Rensburg Fund Management (RFM) subsidiary. The business was acquired as part of the takeover of Rensburg Sheppards in June. Carillion said the coalition government's cuts on the Building Schools for the Future programme will not have a "material impact" on the group's orders.