Continuity mistake: When Pascal's henchmen infiltrate Buckingham Palace, and force the Queen to abdicate, if you look very closely on the abdication document it is dated the twentieth of March 2003. Yet in an earlier scene where Johnny English is photographed by the speed camera that has the date 21/03/03, obviously the abdication was filmed before the car chase, and therefore the dates get mixed up.
Other mistake: In the chase scene, where Johnny and Bough are chasing the hearse, when Bough and Johnny are discussing where the hearse went, Johnny says "They were heading south." Then he turns the steering wheel to his right, yet when it shows a view of the truck it turns to it's left. (00:22:15)
Lorna Campbell: You obviously haven't met our host, Pascal Sauvage.
Johnny English: Oh! Thank God! You know, I think I'd rather have my bottom impaled on a giant cactus than exchange pleasantries with that jacked up Frenchman. In my opinion, the only thing the French should be allowed to host is an invasion.