LONDON - It's not every day the American president's driver is told to move his bulletproof car.
But the Queen's handlers made the request Wednesday after President Barack Obama's reinforced Cadillac limousine was found to be blocking the garden entrance driveway at Buckingham Palace.
After it was moved, Jaguars carrying Prince Charles and other members of the Royal Family pulled up for the Queen's reception for leaders attending Thursday's G20 summit.
Obama and his wife Michelle -- wearing a black and white dress, pearls and a black coat -- were two of the first dignitaries to meet the Queen, who wore a salmon-coloured dress and her trademark pearls.
During their private meeting, Obama and his wife gave the Queen a personalized iPod with video footage of her 2007 visit to Washington and Virginia. She was also given a rare songbook signed by composer Richard Rodgers.
In return, the Queen and her husband, Prince Philip, gave the Obamas a signed portrait of themselves.
The Queen has met with 11 of the last 12 U.S. presidents, including a meeting that took place with Harry Truman when she was a princess, according to Buckingham Palace spokesman David Pogson.
The only president she did not meet was Lyndon Johnson. His widow later met the Queen after the president's death.
The Queen and her husband entertained the Obamas in her private audience room, which overlooks the palace gardens where thousands of daffodils and other flowers were in bloom.
The room, which is part of the Queen's private quarters, is frequently used for private meetings with visiting leaders. Prime Minister Stephen Harper also visited with the Queen on Wednesday.
After her meeting with the Obamas, the Queen held a reception for all the world leaders attending the summit.
They gathered in the palace's picture gallery and were served champagne, wine and canapes of chicken with zucchini on skewers, mini Cornish pasties, smoked quail eggs, foie gras and tiny rolls of duck filled with melon.
The Queen chatted with Italian Prime Minister Silvio Berlusconi while French President Nicolas Sarkozy held an animated discussion through an interpreter with U.S. Secretary of State Hillary Clinton.
Prince Charles shared a joke with Brazil's President Luiz Inacio Lula da Silva while his wife, Camilla, held a long talk with Michelle Obama.
"It was a wonderful visit," Obama shouted to reporters as he and his wife left the palace. "Her majesty is delightful."
Several hundred people gathered outside Buckingham Palace and cheered as soon as they saw Obama.
Earlier in the day, Obama used a news conference with Prime Minister Gordon Brown to say how much he and his wife were looking forward to meeting the Queen, praising her as a model of "decency and civility."
Brown and his wife, Sarah, were holding a dinner at Downing Street for all of the leaders attending the summit.
Celebrity chef Jamie Oliver was cooking dinner for the G20 leaders. The main course was slow-roasted Welsh lamb accompanied by wild mushrooms, asparagus and potatoes from Jersey in the English Channel. Vegetarian leaders were being offered potato dumplings and asparagus.
Appetizers include baked Scottish salmon with vegetables and goat's cheese from Hertfordshire with roasted shallots. Bakewell tarts and custard is on the menu for dessert.
France's Sarkozy, who had hinted he would walk out of the G20 if leaders didn't agree to concrete plans on tighter financial regulations, was the last to arrive for the dinner.
Obama sat next to German Chancellor Angela Merkel -- who has joined in Sarkozy's calls -- while Chinese President Hu Jintao sat between Brown and Sarkozy.
