A major oil discovery for BP sent the group's shares racing to their highest close for nine months today, but failed to lift the wider market.
The FTSE 100 Index languished in the red for the second session, closing down 2.2 points at 4817.6, with little in the way of corporate news to add momentum.
BP became the centre of attention after it announced a "giant" oil find in the Gulf of Mexico, which it said had the potential to match production at some of its biggest projects.
It rose more than 4%, or 22.15p to 541.65p - its highest level since early January - thanks to the news.
However, other stocks were not so fortunate as fears that the recent surge in shares had gone too far have made investors jittery in a traditionally turbulent month for stock markets.
Financial shares were among those to feel the heat, with Royal Bank of Scotland down 2.2p at 53.3p and Lloyds Banking Group off 6.6p to 99.41p, amid reports it had won backing from its investors to raise £10bn (€11.4bn) to reduce its dependence on the taxpayer.
Insurance firms were also under pressure on speculation the sector may have to raise £50bn (€57bn) to meet capital requirements under new European solvency rules.
Legal & General was the top FTSE 100 faller, losing 6.45p to 68p - almost 9% - with declines compounded as it turned ex-dividend, meaning new investors will not be able to participate in the next dividend payout.
Aviva lost 15p to 390.3p, while Old Mutual lost 2.75p to 88.6p.
Mining firms were dragged down as metal prices dipped on a slightly firmer dollar. Vedanta Resources fell 67p to 1631p and Kazakhmys slid 33.5p lower to 920p.
A host of defensive shares joined BP on the risers board as investors sought safer havens, with Lambert & Butler maker Imperial Tobacco up 26p to 1749p.
Supermarket Morrisons was also a strong performer, up 9.8p to 285.8p after Deutsche Bank lifted its target price. Rivals Tesco and Sainsbury's both gained ground, rising 3.6p to 371p and 1p to 325.6p respectively.
In the second tier, Currys' owner DSG International reported another sharp fall in UK sales, but said a stronger international performance helped limit the overall decline to 6%.
Despite chief executive John Browett talking of an "encouraging" start to the year, shares failed to hold on to early gains, later standing just 0.7p higher at 27.73p.
Also in the FTSE 250, fund manager Hargreaves Lansdown fell 2.3p to 245.7p despite posting a better-than-expected 20% hike in pre-tax profits to £73.1m (€83.3m) for the year to June 30.
The biggest Footsie risers were BP up 22.15p to 541.65p, Randgold Resources ahead 131p to 3689p, Morrisons up 9.8p to 285.8p and Centrica up 8.7p to 255p.
The biggest Footsie fallers were Legal & General down 6.45p to 68p, Lloyds Banking Group off 6.6p to 99.41p, BT down 5.45p to 130.4p and Royal Bank of Scotland down 2.2p to 53.3p.