Blooper

During the fighting scene in the study, the man caught in the ladder changes from a British guard to an Asian guard and back again.

During the fight with Rathbone, Roy's knocked outside of the tower onto the hands of the clock. While the camera inside focuses on Chon and Rathbone the silhouette of Chon's arms can be seen, but not Roy's.

Charlie's face is dirty when Wang and O'Bannon meet him. But a few minutes later, when Charlie, hiding in a crate, sneaks a peek at Wang fighting a group of thugs, his face is clean.

During the fight in Rathbone's study one of the attackers is wearing chest armor. When the fight escalates near the ladder he is knocked over to the right of the ladder while the other attacker is stuck in the ladder. When he gets kicked by Chon he is on the left side of the ladder with no armor. In the next angle he is already standing and coming back to attack with his sword and armor.

When Roy, John and Charlie are in the fancy house, the level of the brandy in the serving cup changes from shot to shot.

Non-British citizens, such as Chon and Roy, would be not dubbed with a sword when knighted, and would not be given the title "Sir".

After being Knighted the three of them turn to face the audience, thus turning their backs to the monarch. After being knighted a person backs away from the monarch.

Spotted Dick is a steamed pudding (cake) containing fruit. It is not what was shown.

The Union flag is hanging the wrong way round on the Big Ben Tower.

Arthur Conan Doyle was a Scottish doctor by trade, and not an English detective working for Scotland Yard, as portrayed in the film.

When one of the men stabs at Chon Wang during the Fleet Street fight, he hits a wooden box instead. The rubber blade of the knife curls almost all the way back as it hits the box.

When Lord Rathbone is talking to Chon, who is pretending to be an Indian Maharaja, at the party, he establishes that he has spent time in both China and India. Most Brits in the late 19th century might not have been able to tell an Indian accent from a Chinese accent, but as Lord Rathbone has spent time in both countries, he should easily have known that Chon was lying about being Indian, simply by his Chinese accent.

During the fight in Rathbone's study, we can see the Chinese stuntman that is obviously doubling for an English attacker caught in the ladder.

While swimming under water, streaks of fired rounds go through the water missing the swimmer (Jackie Chan). All supersonic bullets (up to .50-caliber) disintegrated in less than 3 feet (90 cm) of water, but slower velocity bullets, like pistol rounds, need up to 8 feet (2.4 m) of water to slow to non-lethal speeds. However, as most water-bound shots are fired from an angle, less actual depth is needed to create the necessary separation.

The weapon shown to be a "Gatlin" gun is not a Gatlin gun of the period. It is mounted on a tripod, it uses gas operated belt fed system, it has double thumb triggers, it has a sight system, it has eight barrels rather than six or ten and it has a breech loader on top for the belt fed system. According to the Long Mountain Outfitters, this prop was a Vickers gun combined with a Browning M1917 receiver synced to a motor-driven rotating barrel assembly.

The first commercially available automobile did not appear until 1888, and it looked very different from the cars seen in the movie. The particular Renault automobile owned by Rathbone was made around 1914.

When Roy and Chong are at the Royal Palace, the red uniforms the guards are wearing didn't come around until 1904. The film is set in 1887.

One of the film's many "historical cameos" is made by Jack the Ripper. The film is set in 1887; Jack the Ripper's crime spree began in August 1888.

In the "Kung Pow Chicken" scene, when Chan is fighting with the thugs, he traps one of the thugs' hand in between two boxes. The thug is wearing modern shoes.

The London street urchin that O'Bannon chases turns out to be Charles Chaplin. The film is set in 1887; Chaplin wasn't born until 1889.

When Roy is sitting with his back to the revolving fireplace, we can see a crewmember actually moving the fireplace on the left-hand side.

The real Stonehenge is located in the middle of flat grassland with roads on two sides, not amongst hills.

After the escape from the burning barn in London, Roy and Chon crash at Stonehenge. Stonehenge is, in fact, 85 miles away. However, Lord Rathbone's residence is clearly in the country, not in London. In fact, Stonehenge is never mentioned and there are many stone circles in the UK, but it is clearly meant for viewers to assume it is Stonehenge.

Stonehenge only has 1 road running past it.

When John sits Lin down for the serious private talk about Roy, they both speak in English. It would seem more logical for them to speak in Mandarin, in order to keep a certain eavesdropper from listening in.

There was no one who could vindicate the main characters. There was no one who could corroborate their story because there was no one else to hear Rathbone confess, and their only source of information was a disgraced police officer.

Lord Rathbone would not have had to kill 10 members of the Royal family, but at least 50 to gain the throne. Because British royal rule is not salic (meaning passed down along the male line, but rather, male preference, meaning male children and their descendants first, followed by the next child and their descendants etc.), succession is Victoria's eldest son followed by his children, sons first, after that it would go to her second son and his children, then the third son and his children etc. and then her daughters and their children and even grandchildren. After that it would go to Victoria's cousins and their children, and the first cousin possible to be in the house of lords was at least 51st in line. So Rathbone would actually have been at least 51st in line, probably even further down the line to be his age; far from even Roy's '20th in line' jibe.

When Chon and Roy are talking following being picked up by Lin on the way from Stonehenge, Chon calls Roy "Owen".

Lord Rathbone addresses Queen Victoria as "Your Highness". The correct form of address is "Your Majesty" or "Ma'am", although a Lord who is tenth in line to the throne should have known this.

In the ceremony when someone is made a Knight or a Dame, the Monarch speaks that person's full name. Doyle was born Arthur Ignatius Conan Doyle. When Queen Victoria knights him, she doesn't say "Ignatius". Nor does she speak Wang's and O'Bannon's full names.

When Lord Rathbone revealed an automatic Gatling gun and said it was British ingenuity he was partially incorrect. The Gatling gun was a hand cranked weapon that was created by Richard Gatling, American, in 1861 and patented May of 1862. The first automatic, self-powered machine gun was invented by an American born Briton, Sir Hiram Maxim in 1884 and first displayed in 1885. The Maxim gun bared little resemblance to the Gatling gun. Automatic Gatling style guns did not come about until the 1940's.