LONDON (ShareCast) - London’s top stocks have narrowed earlier gains but miners are still keeping the rest of the index in the blue.

Higher copper prices prompted Lehman Brothers to upgrade price targets across the mining sector this morning. The broker raises its copper price estimates for 2008 and consequently lifts its price targets on Xstrata, BHP Billiton and Anglo American.

Platinum miner Lonmin leads the way even though it cut its estimate of full year production from 860,000oz to 775,000oz due to the ongoing power supply problems in South Africa.

Johnson Matthey was among the major fallers after UBS downgraded the speciality chemicals company to ‘sell’ from ‘neutral’ on valuation grounds.

Alliance & Leicester is the weakest Footsie member, though banks generally are having another tough day on credit crunch worries. Royal Bank of Scotland, Barclays and HBOS are also lower.

GlaxoSmithKline is to boost it presence in sirtuins, a recently-discovered class of enzymes, with the acquisition of Sirtris Pharmaceuticals for approximately $720m. Through the acquisition of Sirtris, GSK said it will significantly enhance its metabolic, neurology, immunology and inflammation research efforts.

Crude oil prices near $120 per barrel are hurting airlines British Airways and Easyjet and bus group National Express.

Shares in Dana Petroleum rallied on news that the group has discovered oil at the West Rinnes structure in Block 210/24a in the North Sea.

Sub-prime lender Cattles is a big gainer even though it is to raise £200m through a up to 163m new shares at an issue price of 128p, a deep discount to yesterday's closing price of 219.5p. The 9-20 rights issue has been fully underwritten by Citi and HSBC. The funds will be used to help its application for a banking licence, Cattles said.

Vaccine maker Acambis accompanied news of a ten-year contract worth $425m to supply the United States government with a smallpox vaccine with a placing to raise £40m.

Mobile power specialist Aggreko reports revenue grew by 20% in the first three months of the year, adding it confident of further good progress in 2008.

Drug developer Alizyme slumped on news it has ended development of its drug renzapride in constipation-predominant irritable bowel syndrome following results from a final stage clinical trial.

Acquisitive environmental consultant RPS Group said results in the first quarter of 2008 have “substantially exceeded” those seen in the same period of last year.

Worries about its applications side sent shares in IT hardware supplier Morse slipping back despite progress elsewhere.

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