Oil firm BP has suffered its biggest one-day shares fall for 18 years after the group failed once more to halt the devastating Gulf of Mexico oil spill.
Shares plunged by as much as 17% at one stage yesterday, before settling around 13% lower — wiping some £12bn off its market value.
The stock tumbled into the red after its latest attempts to block the leaking oil well proved unsuccessful and amid mounting fears over the ultimate financial toll on the company.
One analyst said the relentless oil leak — now the worst ever in US history — had the potential to “break BP” if the well was not brought under control soon.
BP’s so-called “top kill” operation to cap the well with mud and other debris proved unsuccessful over the weekend and the company is now working on using robot submarines in the latest move to stem the flow of oil.
But this technique has never been used before and it is far from certain that the procedure will work, potentially leaving BP with no other option than to drill relief wells — which could take until August to complete.
BP admitted today that the total cost of the response had reached $990m (£682.3m) so far.
However, the cost to BP could be more long-term, with the risk of tough punitive action from the US government.
Some market analysts believe the shares fall has been an over-reaction, although the group's stock market troubles are unlikely to ease until the well has been brought under control.