
President Obama and British Prime Minister David Cameron participate in a joint news conference at Lancaster House in London on Wednesday, May 25, 2011. (AP Photo/Charles Dharapak)

President Obama and Britain's Prince Philip review the Scots Guard during an official arrival ceremony at Buckingham Palace in London on Tuesday. (Associated Press)

Britain's Queen Elizabeth II and Mr. Obama toast at a state banquet in London's Buckingham Palace on Tuesday. Mr. Obama brought gifts for the queen and other members of the British royal family. (Associated Press)

President Obama (left) and British Prime Minister David Cameron react as they play table tennis with students during a visit to the Globe Academy in London on Tuesday, May 24, 2011. (AP Photo/Charles Dharapak)

President Obama (left) and British Prime Minister David Cameron high-five as they play table tennis at Globe Academy in south London on Tuesday, May 24, 2011. (AP Photo/Paul Hackett, Pool)

President Obama (left) and British Prime Minister David Cameron play table tennis at Globe Academy in south London on May 24, 2011. (Associated Press)

President Obama, accompanied by the Very Rev. John Hall (second from right), the dean of Westminster Abbey, shakes hands with members of the historic church's choir during a visit to London on Tuesday, May 24, 2011. (AP Photo/Carolyn Kaster)

Police officers check a manhole on Whitehall in London ahead of the visit of President Obama to 10 Downing St. on Tuesday, May 24, 2011. Mr. Obama is on a two-day state visit to the United Kingdom. (AP Photo/Sang Tan)

Islamic supporters protest outside Downing Street in London against the visit of President Obama on Tuesday, May 24, 2011. Mr. Obama is on a two-day state visit to the United Kingdom. (AP Photo/Sang Tan)