Factual error: Whenever one or more of the mutated, super venomous snakes attack someone, you can hear a rattling sound because they evolved from rattle snakes. However, it frequently shows the tips of the snakes tails, and they are completely bare. How can they constantly make that noise if they don't have rattles?
Factual error: As the Khan family enter Bradford, they go over a sleeping policeman. These weren't around in 1971. (00:30:45)
Factual error: The scene where Michael frantically arrives at the FBI headquarters, he drives the Contour up over the movable vehicle barrier. The movable vehicle barriers that are in place at the FBI headquarters, both pre and post 9/11, are steel ramp type barriers angled upward toward the entering car and lowered when needed. The ramps are about as high as the top of the Contour's hood and the Contour would have just gotten wedged under the opening of the barrier ramp. And there wasn't enough of a "ramp" in front of the barrier to floor it and jump the car over the barrier (ala Dukes Of Hazzard), hence the barrier system would really work.
Factual error: In the scene where Arthur tries to convince Gertrude to not force her husband to "retire from public life" you can see (in the close up shots) that his right ear has been pierced twice which is inconsistent with the time period.
Factual error: One of the operetta excerpts shown in the movie is the humorous song "This Helmet I Suppose," during which Princess Ida's three brothers are supposed to remove their armor piece by piece, finding it heavy, hot and awkward. Partly as a result of this, the three are soon afterwards quickly and easily defeated in combat. In the film, however, only Arac, the brother singing the verses (played by Richard Temple (played by Timothy Spall)), removes his armor. The others simply stand still. (This might have made the battle scene end differently if it was shown on screen!)
Factual error: In the very last scene the train is stopped by the Russian army and their tanks. The tanks are T-54's, which were not produced until 1955. (01:53:28)
Factual error: All of the computers show a Mac OS when they're booted up. However, when Peter is shutting his computer down to try to escape his boss, the computer shuts down to a C: prompt. For those not technically minded, a C: prompt is only seen on IBM-compatible PCs, never on Macs. (00:19:20)
Factual error: Eight months after Craig has taken over JM and made him into a puppeteer JM's hair is much, much longer than it could have grown within that period. (01:25:00)
Factual error: The clothing and most noticeably the armour of the Viking warriors is a very higgledy piggledy collection of dress from different places and times in history. Only Buliwyf actually seems to be wearing armour of Viking origin, some of the others have Spanish Conquistador armour and helms from centuries after the film is set and another wears a Roman gladiator's helm complete with face mask, another of the group is seen to be wearing a kilt (the redhead conveniently played by one of the two Scottish actors used as Vikings)which may well have been worn concurrently by their celtic neighbours but his kilt is quite modern in design.
Factual error: At many points, particularly when Nixon has resigned, the soldiers around the White House are using modern M16A2 rifles, which I don't think the US military used until the 1980's.
Factual error: The film takes place around 1830, but you can see a character using a Colt Navy 1851, which was made 21 years later actually.
Factual error: Tony the disco bandit is dancing just after Casanova is released. He looks at the record player and sleeve. The record is a relatively modern vinyl stereo LP at a speed of 33 RPM. But the record player is a really antique machine for bakelite mono records that play at 78 RPM. Even if it could play the record, the sound would have been completely wrong.
Factual error: In the film, Carter leaves the military with service ribbons. In reality, he was discharged after being court-martialed.
Factual error: In the fight scene on the train, Silent Bob hits the "Door Open" button to throw Bartleby out of the last car of the train. Such doors are kept locked.
Factual error: When they are at the Greek restaurant, there is a writing on the wall in Greek. It reads "ΚΑΤΣΟ ΝΑ ΣΚΑΣΟ" but the correct spelling is "ΚΑΤΣΩ ΝΑ ΣΚΑΣΩ"
Factual error: The events of the film take place in the early decades of the 18th century. However, in shots outside the front door of the house throughout the entire film there is a large rhododendron bush, a species which didn't arrive in England until the mid 19th century.
Factual error: In a scene in a bar the music playing is Blur's Song 2, which wasn't released until 1998 and a Kula Shaker song which wasn't released until 1996, by which time Nick Leeson was firmly in prison.
Factual error: The song Olga and Lensky sing at the piano was written in the first half of the 20th century, while the events happen about 100 years earlier.
Factual error: When Heather pulls up in her car and confronts Oz after seeing Stifler making fun of her on the Lacrosse field her car has an actual Michigan license plate on it. One of the producers even pointed it out on the DVD thinking that it was a great attention to detail. The only problem with that is the plate is on the front bumper. Michigan does not have licence plates on the front, only in the back. (00:41:10)
Factual error: When the boy is carried home after being stung, several people mention to 'take out the stingers'. As he was stung by wasps, you don't need to do that.