BP revealed yesterday it has so far spent $2 billion on the Gulf of Mexico oil spill, after an internal BP document suggested the gusher might be spewing far faster than initially feared.

In a statement to the London Stock Exchange, the embattled British energy giant said its costs to date included ongoing efforts at containment, relief well drilling, grants to Gulf states, claims paid to affected individuals and businesses, and costs incurred by the US government. The announcement comes after a week of White House arm-twisting that prodded BP to agree to a $20-billion fund to pay claims and a stepped up oil recovery effort in the Gulf.

Meanwhile on Sunday, US outrage was further heightened by the discovery that BP's own worst-case scenario estimate of the amount of oil leaking into the Gulf of Mexico was some 20 times higher than its early public estimates.

Media reports that chief executive officer Tony Hayward had attended a yacht race off the Isle of Wight the day after he handed over day-to-day management of the oil leak response, also prompted one of the sharpest expressions yet of administration anger with BP.

"Well, to quote Tony Hayward, he's got his life back, as he would say," White House chief of staff Rahm Emanuel said, referencing the BP boss's now-notorious slip.

"And I think we can all conclude that Tony Hayward is not going to have a second career in PR (public relations) consulting," Mr Emanuel told ABC's This Week.

"This has just been part of a long line of PR gaffes and mistakes."

Mr Emanuel then assailed BP for its response to the worst oil spill in US history, saying it must be forced to do more.

The company has been regularly faulted for the pace of its response to the disaster, triggered by the April 20 explosion that ripped through the Deepwater Horizon rig it leased, killing 11 workers.

Over the past week, the British energy giant has called in more ships and equipment to the area and said it would significantly boost the amount of oil captured from its busted well.

But a key US congressman Ed Markey, a vocal critic of BP and its handling of the disaster, tore into the firm after releasing an internal BP document that showed the energy giant's own worst-case estimate of the leak was much higher than it publicly stated.

"First they said it was only 1,000 barrels, then they said it was 5,000 barrels, now we're up to 100,000 barrels," he told NBC's Meet the Press, saying BP was "either lying or grossly incompetent".

US government estimates now put the leak at 30,000 to 65,000 barrels a day - or, at the upper end of the scale, more than 2.5 million gallons of oil each day.

BP rejected Mr Markey's charge, noting that the conditions it had stated for the worst-case scenario to develop were not in place then, and are not in place now.

"It's completely misrepresenting what we're saying," BP spokesman Robert Wine told AFP. "We were saying that if two conditions were met simultaneously - one that we got the modelling restrictions wrong and if the blowout preventer were removed - then we could have 100,000 barrels of oil."

He said the estimate "has nothing (to do) with the amount of oil that's actually escaping at the moment."

BP also raced to defend Mr Hayward's yacht outing on vacation with his son in Britain, which a spokesman called his "first non-working day since this started."

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