Factual error: Cedric mentions that the Imperial State Crown contains the "Star of India" and calls it the second largest diamond in the world. The Star of India is actually a star sapphire and is housed in an American museum. In the actual crown is a gem called the Star of Africa, which is the second largest diamond in the world.
Continuity mistake: The scene is where Duncan is sitting across from Ralph trying to convince him that he's the king. It's a taco stand or something. At the start of the scene you see a bottle of Tabasco sauce on the table. In the next view, the bottle is gone and Ralph gets up to get a bottle of Tabasco sauce from the counter.
Audio problem: Apparently, Ralph's surname was changed at the last minute from the British Royal Family surname of "Windsor" to "Windham." There are several points in the film, where there is a lip-sync problem, due to the differences of the name, because it has been dubbed.
Factual error: There are numerous references made to the Finnish Royal Family, and they even make an appearance. Only problem is, Finland doesn't have a Royal Family.
Revealing mistake: After Ralph goes to the club and meets Miranda there's a scene where the front page of The Daily Telegraph newspaper (dated March 9, 1990) is show. It has the headline "From Uncle Same to Buck 'ham'" with a picture of Ralph. The article under the headline hasn't been changed from the original news story. The article begins, "Mounted police broke up a mob that had looted shops and attacked a police station in Hackney, ease London, last night after a poll tax protest by up to 5,000 people blew up into a riot. With running battles between officers and demonstrators. Scotland Yard said at least 50 people were arrested and several police officers hurt in the worst violence yet seen in the campaign against the community charge."
Continuity mistake: There's a scene near the start where Duncan is sitting across from Ralph at a street food van. There are two plastic cups of fizzy drink on the table. The one nearest Ralph is initial tilted, as if something is under one side of the base. Part way through the conversation, without anyone touching it, it straightens up.
Factual error: When King Ralph arrives at the banquet, he is introduced as "King Ralph the First." This is an error as reginal numbers are only assigned when there is a second monarch with the same reginal name, hence "Queen Victoria", not "Queen Victoria I."
