US President Barack Obama (L) and US First Lady Michelle Obama (R) meet Britain's Prince William, the Duke of Cambridge (2nd L) and his wife Catherine, the Duchess of Cambridge (2nd R) at Buckingham Palace yesterday during the president's state visit.Photo: AFP

The Queen has greeted yesterday US President Barack Obama, and his wife Michelle, at the start of his first UK state visit.
They have laid a wreath on the Tomb of the Unknown Warrior in Westminster Abbey and will attend a state banquet at Buckingham Palace.
It came after David Cameron and Obama spoke of "essential" UK-US ties.
In a joint article in the Times, Obama and Cameron said of their countries' relationship: "Ours is not just a special relationship, it is an essential relationship - for us and for the world.
"When the United States and Britain stand together, our people and people around the world can become more secure and more prosperous,” said the joint statement.