Updated

For President Barack Obama, a state dinner hosted by the British queen is much more than a chance to dine on Windsor lamb washed down with 50-year-old port. It's also an opportunity to bask in the grandeur of Britain's monarchy, still glowing from the success of a princely wedding watched around the world.

Large British and American flags lined the Mall, where, less than a month before, Prince William and his new bride, the Duchess of Cambridge, rode to Buckingham Palace. The nearby Green Park still bore large bare patches where the world's media had camped out for the marriage.

Inside the palace, the crimson-carpeted ballroom was laid out with 19th-century silverware, Louis XVI porcelain and fragrant floral arrangements more than 12 feet (four meters) tall. Every gilded ornament had its own rich history — the Rockingham dessert service, for example, was first used for Queen Victoria's coronation in 1838.

The 170 or so guests joining the Obamas for dinner include Britain's prime minister, senior royalty, ambassadors, business leaders, top brass, leading academics, prominent nobility and even the archbishop of Canterbury — who officiated at William's April 29 wedding.

No white-tie state dinner would be complete without a side helping of celebrity. Tom Hanks was on the guest list, as was Tim Burton, Kevin Spacey and Helena Bonham-Carter — who won plaudits for her recent portrayal of the queen's mother in the Academy Award-winning movie "The King's Speech."

The menu, printed in French on dainty white cards, included sole, Windsor lamb with basil, green bean panache and Charlotte a la Vanille for dessert. Wines include Chablis Grand Cru Les Clos 2004 and Royal Vintage Port from 1963.

The music program included a march, a waltz, a German dance and "My Fair Lady" by Frederick Loewe. When an Associated Press reporter was ushered into the ballroom, the band was sharpening its rendition of "The Star Spangled Banner."

All this pomp and circumstance has a purpose. State visits aren't personal favors from the queen — they're arranged by Britain's government as a way of courting allies and rewarding friends. The queen's guestlist — and even her dinner toast — is coordinated with officials.

The forest of white ties, the Scots Guards' pipe program, and the Paupiette de Sole et Cresson are all meant to leave everyone looking a little more regal. But even at Buckingham Palace, it's impossible to banish all the discordant notes.

Just beyond the palace's black-and-gold gates, about a dozen orange-jumpsuit clad demonstrators were rallying for the freedom of Guantamano Bay detainee Shaker Aamer, a former British resident who had been held without charge for some nine years. One man wore plastic shackles and an Obama mask.