But a day earlier, Obama blasted U.S. lawmakers and Tea Party activists for criticizing his response to the nation's worst environmental disaster, suggesting they are being hypocrites.
"I think it's fair to say, if six months ago, before this spill had happened, I had gone up to Congress and I had said we need to crack down a lot harder on oil companies and we need to spend more money on technology to respond in case of a catastrophic spill, there are folks up there, who will not be named, who would have said this is classic, big-government overregulation and wasteful spending," he told Politico in an interview.
Obama also suggested the criticism coming from anti-big government protesters, such as Tea Party activists, was hypocritical.
"Some of the same folks who have been hollering and saying 'do something' are the same folks who, just two or three months ago, were suggesting that government needs to stop doing so much," Obama said. "Some of the same people who are saying the president needs to show leadership and solve this problem are some of the same folks, who just a few months ago, were saying this guy is trying to engineer a takeover of our society through the federal government that is going to restrict our freedoms."
But Obama sang a much different tune to Cameron on Saturday when the two leaders held a "warm and constructive" telephone conversation for more than 30 minutes, Cameron's Downing St. office said.
Cameron's office said the prime minister “expressed his sadness at the ongoing human and environmental catastrophe,” but stressed BP's economic important to Britain, the U.S. and other countries.
Then Obama told the prime minister "that his unequivocal view was that BP was a multinational global company and that frustrations about the oil spill had nothing to do with national identity. The prime minister stressed the economic importance of BP to the U.K., U.S. and other countries. The president made clear that he had no interest in undermining BP's value.”
Cameron is under pressure to get Obama to tone down the criticism fearing it will hurt the millions of British retirees that hold BP stock. The company's stock has lost 40 percent of its value since the April 20 oil rig fire.
Rep. Darrell Issa, R-Calif., fired back at Obama over his criticism of Congress, saying hypocrisy is no excuse for inaction "in addressing the dysfunctional and corrupt nature of the Minerals and Management Service" -- the agency that oversees offshore drilling.
"If President Obama had exercised some long overdue leadership and called on Congress to address the cozy relationship between MMS and the industry they regulate, I would have been the very first person to partner with him and give MMS the overhaul it desperately needs," Issa said in a written statement.
"After 10 inspector general reports, 10 GAO reports, a congressional investigation, the real question is, why did it take such a catastrophe for the president to call for action," he said.
Obama has sharpened his attacks on BP in recent days as the company struggles to stop oil gushing from its ruptured deepsea well.
Obama has said he would have fired BP's top executive, if he were in charge, and has supported the idea that the oil company suspend its quarterly dividend.
In a sign the company feels the pressure, BP said Saturday that its board would meet Monday to discuss deferring its second-quarter dividend and putting the money into escrow until the company's liabilities from the spill are known. BP said no decision had yet been made.
Obama also has reproached BP for spending money on a public relations campaign and occasionally refers to "British Petroleum," although the company years ago began using only its initials and is a far-reaching international corporation with extensive holdings in the United States, including a Texas refinery and a share of the Alaska oil pipeline.
This past week, the usually measured Obama said in a television interview, "I don't sit around just talking to experts because this is a college seminar; we talk to these folks because they potentially have the best answers -- so I know whose ass to kick."
The Associated Press contributed to this report.