Market Report: North Sea platform's gas leak hits energy giants

It is no surprise that a leaking rig in the middle of the sea prompts minds in the Square Mile back towards the Gulf of Mexico tragedy. As Total's Elgin platform continued to pump out gas, investors were pulling out of the blue-chip energy giants with BG – which holds a 14.1 per cent interest in the North Sea project – the worst hit.

Following the news that one option to stop the flow could take as long as six months, BG was pegged back 44p to 1,475p, although it was in better shape than the platform's operator, Total. The French firm's share price shed 6 per cent during trading in Paris, despite its insistence that comparisons couldn't be made with the 2010 Gulf of Mexico disaster.

With Capital Spreads' Angus Campbell saying it "brought back horrible memories of the... oil spill in the Gulf of Mexico", both BP and Royal Dutch Shell also finished in the red despite having no stake in the field, retreating 10.55p to 471.35p and 28.5p to 2,239.5p respectively.

Coincidentally, the former announced it had agreed a deal to sell some of its North Sea assets for $400m (£250m), with the oil giant continuing to raise funds to go towards the cost of the Gulf of Mexico tragedy.

Although in early trading the FTSE 100 was continuing to rally, by the bell it had fallen 33.15 points to 5,869.55. Figures from Spain's central bank showed the country had slipped back into recession, while disappointing economic data from the US did not help sentiment.

Royal Bank of Scotland shot up 0.92p to 28.67p on reports that Britain has been discussing a possible sale of some of its stake to Abu Dhabi investors. Although Investec's analysts said "we won't hold our breath" over a sale, they added that "the emergence of a (potential) marginal buyer of size is welcome".

Resolution retreated 6.7p to 268.2p after blaming falling stock and bond prices for its decision to postpone a £250m return to its investors, with the insurer also unveiling plans to divide itself into two parts.

On the FTSE 250, bid talk around Drax was heating up. Saying the UK's largest power station was the "only potential takeover candidate" among the European electrical utilities, Exane BNP Paribas' Benjamin Leyre suggested Centrica (2.2p higher at 317.2p) as one possible aggressor. However, with Mr Leyre conceding that any potential bidder will hold off until there is further clarity on government support for biomass fuel, Drax slid back 9p to 531p.

He was less impressed by recent rumours claiming International Power's 70 per cent shareholder GDF Suez may try to buy the rest of the energy group, arguing that the French firm "does not have a sufficiently comfortable balance sheet".

Deutsche Bank's Martin Brough was in agreement, saying such a scenario was "unlikely in the near term", as he downgraded his rating to hold. However, at the same time vague speculation was being revived that GDF could make a move soon, as International Power – which has climbed nearly 20 per cent since January - edged back 2.3p to 380.1p on the blue-chip index.

Back among the mid-tier stocks, Spirent Communications powered up 3.3p to 156.6p after it was chosen as one of Goldman Sachs' favourite UK tech stocks. The list also included chip designer Arm Holdings (up 3.5p to 601p) and software firm Aveva (up 16p to 1,712p), while the broker's scribblers added that "M&A activity in the global technology industry is likely to accelerate".

A late spurt saw Petra Diamonds close 12.3p stronger at 188.2p following the announcement by Rio Tinto – which eased up 22p to 3,386.5p – that it may sell its diamond business. Northland Capital's Ryan Long suggested this could give Petra and its fellow diggers "the opportunity to expand their asset bases or merge to create larger, diamond-focused miners".

PZ Cussons took the wooden spoon as the soap maker's second profit warning in under four months smacked it back 9.82 per cent to 301.3p.

Cable & Wireless Worldwide was also deep in the red, sinking 1.75p to 35p amid nervousness ahead of tomorrow's deadline for Vodafone (0.25p lower at 174.05p) and Tata Communications to decide whether to bid for the telecoms firm.

As bid rumours continued to do the rounds, Gulfsands Petroleum spurted up 18.89 per cent to 160.5 on AIM. The idea has been greeted with much scepticism thanks to the explorer's focus on Syria.

Meanwhile, Bellzone Mining was lifted 0.75p to 34p following the news that its partner China Sonangol has once again raised its stake in the West Africa-focused group, this time to above 15 per cent.

Robert Walker is already proving popular with punters in Enterprise Inns. The chairman designate, who takes up the role next weekend, has splashed out almost £120,000 on shares in the debt-laden pub group, news of which pushed it 0.75p higher to 55.75p on the small-cap index.