Query: When are state banquets held?
Context: State banquets also take place in the Ballroom; these formal dinners are held on the first evening of a state visit by a foreign head of state. On these occasions, for up to 170 guests in formal "white tie and decorations", including tiaras, the dining table is laid with the Grand Service, a collection of silver-gilt plate made in 1811 for the Prince of Wales, later George IV.