The heavy trading would provide excellent cover for any possible predator wishing to build a stake. In the past year British Petroleum has been linked with Gas and in the past few days PG had made noises suggesting it could nurse predatory ambitions. The generator intends to buy in 10 per cent of its capital, an exercise that will cost pounds 400m. Its shares were unimpressed, falling 8p to 529p.National Power, expected to engage in a similar operation, slipped 4p to 516p and most of the distributors gave further ground.The implosion at British Gas, with poor figures following the Draconian Ofgas measures, took another 14p off the shares leaving them at 174.5p. At one time it was off 36.Utilities were again deep in the doldrums with worries about Labour's threatened windfall tax competing with increasing pressure from the regulators and the Government's somersaults over takeover policy to undermine sentiment.PowerGen started its buy-back with UBS swooping to pick up 4.8 per cent (35 million shares) at 525p from institutions.

The shares have enjoyed a heady run but the temptation to take at least some profits left them 78p lower at 2,800p.SmithKline Beecham, another top drug share, gained 9.5p to 669p following a US presentation.Despite Glaxo's contribution, worth more than 9 points to the FT-SE 100 index, shares had a poor session with Footsie down 22.6 at 3,753.6. Chief executive Sir Richard Sykes said from next year until the end of the decade the group hoped to launch 20 treatments, covering influenza to smoking.The Glaxo blockbuster came as the stock market started to fret about the forthcoming cancer presentation by British Biotech. The granddaddy of the pharmaceuticals showed the hoard of youngsters which have been making all the noise a clean pair of heels. Shares of Glaxo Wellcome, which have lagged the bio-babes as they have attracted cash from almost every investor in town, jumped 47.5p to 836.5p in busy dealing. An encouraging trading statement provoked the sudden interest. First four month sales hit pounds 2.8bn, an 11 per cent increase.