David Cameron and Barack Obama meet in Washington

David Cameron greets the US vice president, Joe Biden, at the British residence in Washington before meeting the US president, Barack Obama Photograph: Stefan Rousseau/PA

Cameron's limousine arrives at the White House Photograph: Chip Somodevilla/Getty Images

Cameron at the entrance to the west wing of the White House Photograph: Chip Somodevilla/Getty Images

Cameron arrives at the White House for a bilateral meeting with Obama Photograph: Michael Reynolds/EPA

Obama talks to Cameron in front of the Oval Office fireplace Photograph: Saul Loeb/AFP/Getty Images

The two leaders are seen through an Oval Office window Photograph: Stefan Rousseau/PA

Cameron and Obama in the Oval Office at the White House Photograph: Oli Scarff/Getty Images

Obama and Cameron arrive for a press conference at the White House Photograph: Pablo Martinez Monsivais/AP

Obama smiles as Cameron makes a point during the press conference Photograph: Saul Loeb/AFP/Getty Images

Andy Coulson, the Conservative party's director of communications, watches as Cameron speaks Photograph: Oli Scarff/Getty Images

Cameron makes a point as Obama listens Photograph: Chip Somodevilla/Getty Images

Obama and Cameron make their way from the podium following after a joint news conference Photograph: Oli Scarff/Getty Images

Cameron and Obama stroll in the grounds of the White House following their meeting Photograph: Downing Street/Crown Copyright/PA

Cameron meets US senators Jeanne Shaheen, John Kerry, Harry Reid and Frank Lautenber on Capitol Hill Photograph: Jim Young/Reuters

Camera crews surround Cameron as he meets the senators Photograph: Win McNamee/Getty Images

Cameron with the House minority leader, John Boehner, and the Speaker, Nancy Pelosi, on Capitol Hill Photograph: Charlie Archambault/EPA

Cameron arrives to lay a wreath at the Tomb of the Unknowns in Arlington National cemetery Photograph: Oli Scarff/Getty Images