By Tom Bergin and Kristen Hays
LONDON/HOUSTON (Reuters) - Britain stuck up for beleaguered BP Plc on Friday against American criticism over a massive Gulf of Mexico oil spill that U.S. scientists said was far bigger than previously thought.
The British backing helped to lift BP shares, which have taken a battering this week as the Obama administration ratcheted up pressure on the London-based energy company over the 53-day-old spill, the worst environmental disaster in U.S. history.
Millions of gallons of oil have gushed into the Gulf since an April 20 explosion on an offshore rig killed 11 workers and ruptured a deep-sea well. U.S. scientists on Thursday doubled their estimate of the amount of oil flowing from the well. (See a graphic on spill rate at http://link.reuters.com/maj68k)
Senior Obama administration officials have threatened to increase BP's liabilities for the spill. Some U.S. lawmakers are pressuring the company to suspend its quarterly dividend to ensure it has enough cash to pay for cleaning up the mess.
BP expects the total bill for the clean-up of the spill, which has affected 120 miles of U.S. coastline and closed down rich fishing grounds, will be $3-$6 billion, an analyst briefed by BP said in a research note on Friday.
BP said it was collecting more oil from its blown-out well, while the Obama administration's point man for the crisis, Coast Guard Admiral Thad Allen, said the company hoped to double its collection efforts to 40,000-50,000 barrels a day by mid-July. (See a graphic on cap system athttp://link.reuters.com/hud49k)
However, the well will not be sealed until August, when a relief well now being drilled is due to be completed. And even with the new government estimates of the oil flow rate, it is still not known exactly how much oil is gushing out.
In London, British government ministers heeded calls to defend Britain's biggest payer of share dividends and stand up to U.S. President Barack Obama, who has fiercely criticized the British company. Some in the British media have portrayed Obama's comments as Britain-bashing.
British Prime Minister David Cameron, who took office in May, is due to discuss the Gulf of Mexico crisis in a telephone call with Obama on Saturday.
"We are all concerned about the human and environmental impact and as the prime minister has said we understand the concerns of the U.S. administration," Britain's Chancellor of the Exchequer George Osborne said after speaking to BP chief executive Tony Hayward by telephone.
"The prime minister is also clear that we need constructive solutions and that we remember the economic value BP brings to people in Britain and America," Osborne added after calls from business leaders, politicians and newspapers to defend BP.
Forty percent of BP's shareholders are in the United States, with the same percentage based in Britain.
BP STOCK
Shares in BP, which has lost tens of billions of dollars in value since the crisis began on April 20, gained 7 percent in London trading, rebounding from Thursday's 13-year low and extending a rally that began in New York on Thursday.
BP's American depositary shares rose 3.5 percent in midday trading in New York on Friday.
"Possibly people have taken heart from the fact that the political rhetoric is not just one side of the Atlantic," said Barclays Capital analyst Lucy Haskins.
Investors appeared unfazed by the news from U.S. scientists that the well's flow rate may be as high 40,000 barrels (1.68 million gallons/6.36 million liters) per day.
The new estimates could have huge financial implications because under the U.S. Clean Water Act, BP and others could face fines up to $4,300 for every barrel leaked.
With more than 2 million barrels of oil already in the ocean, that could means fines of $8.6 billion at least.
Cameron's telephone call with Obama on Saturday will be a tricky test for the two leaders. Both are under pressure to appear tough to voters at home.
Obama, criticized by some in the United States over his handling of the crisis, has been seeking to direct public anger and frustration over the spill toward BP.
For his part, Cameron must show Britons that he is not caving in to pressure from the country's most powerful ally and is standing up for British interests. A spokeswoman for Cameron told reporters the prime minister's telephone call with Obama would be "statesmanlike and workmanlike."
A White House official said BP would likely be discussed but added that that it would be one of a number of issues the two leaders would talk about.
BP DIVIDEND
British investors are particularly concerned about the calls from U.S. lawmakers for BP to suspend its dividend.
"We are considering all options on the dividend. But no decision has been made," BP's Hayward told the Wall Street Journal.
The newspaper said BP, which has seen its market value more than halved since the start of the crisis, may cut or defer the dividend due to be announced on July 27 or offer scrip -- an IOU to shareholders.
BP said on Friday its containment cap system on the ruptured well captured 15,400 barrels of oil on Thursday. The cumulative total collected since the system began operating a week ago reached 88,700 barrels with Thursday's tally, according to BP figures.
Meanwhile, a senior U.S. lawmaker wrote to two of the companies involved in the well, urging them to donate their share of the revenue from the sale of any recovered oil to help restore wildlife habitats along the Gulf Coast. BP has already said it will do this.
"I believe it is essential that all the companies associated with this incident do their part to help mitigate the ongoing human suffering and environmental damage," Nick Rahall, chairman of the House of Representatives Natural Resources Committee, wrote in a letter to Anadarko Petroleum Corp and Mitsui Oil Exploration Company.
(Additional reporting by Eileen O'Grady, Timothy Gardner and Steve Holland and Tom Doggett in Washington, Sarah Young and Estelle Shirbon and Andrew Callus in London, and Chris Baltimore and Kristen Hays in Houston; Writing by Ross Colvin; Editing by Will Dunham)
