Foreign Minister David Miliband told the BBC that it was “a slur both on myself and the government” to suggest that oil was a factor.

Image In Lockerbie, Scotland, a memorial commemorated the victims of the 1988 bombing of a Pan Am jet over the village, which killed 270 people. Credit... Jeff J. Mitchell/Getty Images

The release of Mr. Megrahi, 57, and the officially orchestrated welcome he received from hundreds of flag- and placard-waving Libyans when he arrived at Tripoli airport with Colonel Qaddafi’s son Seif al-Islam el-Qaddafi has incited controversy on both sides of the Atlantic, with the government of Prime Minister Gordon Brown facing bitter condemnation from opposition parties.

On Friday, the White House spokesman, Robert Gibbs, described the scenes in Tripoli as “outrageous” and “disgusting,” adding fresh momentum to President Obama’s condemnation of the Libyans’ behavior on Thursday and the enraged comments of many of the American families whose relatives were among the 270 people killed when Pan Am Flight 103 exploded over Lockerbie, Scotland, in 1988.

The American outrage stirred an intense and bitter debate in Britain over who really bore responsibility for freeing Mr. Megrahi, and why. He had served only eight years of a life sentence handed down by a specially convened Scottish court in the Netherlands, which specified that he serve a minimum of 27 years. David Cameron, the Conservative leader, condemned the release as “wrong” and the product of “completely nonsensical thinking.”

Image In December 1988, police officers and investigators looked at wreckage from Pan Am Flight 103. Credit... Associated Press

The British government and the Scottish government, which made the formal decision to free the bomber under justice powers transferred to Edinburgh under the Blair government, each appeared to be trying to shunt responsibility to the other. Both governments were met with a wave of denunciations in Britain’s national newspapers, which reported the release under banner headlines like “An affront to justice” and “A shabby deal,” many of them alleging that the hunger for oil deals was the original catalyst for letting Mr. Megrahi go.Meanwhile, Mr. Megrahi continued to insist on his innocence, telling The Times of London that he would “put out evidence” exonerating himself and that the people of Britain and Scotland would “be the jury.” Asked who was responsible for the bombing, he said, “It’s a very good question, but I’m not the right person to ask.”