When Watson is arrested by the police after being conned into a small courtyard with only one entrance, two policemen enter and three policemen leave.
During the fight with Slade, Holmes blocks the chain with his right arm. During the meeting with the PM, his left arm is in the sling.
When Holmes And Watson leave the theater at the beginning, they have news of the third ripper victim. Liz Stride was murdered in September, but Watson clearly states that the month is October. No Ripper murders happened in October.
Holmes calls the cab that ran him over a Hansom. He was attacked by a four-wheeled carriage, and Hansoms had two wheels. Holmes had post-traumatic amnesia, didn't remember exactly what ran him down, and assumed it was a Hansom.
The second time Holmes visits Robert Lees, the medium, Lees recounts his vision. The first shot shows a bridge over the river, then pans to a group of men searching the scene. A single yellow line is around the corner of the road. Yellow lines (indicating parking restrictions) were introduced in the UK in 1960. Lees could have been seeing the future; a world where parking lines are painted yellow.
When Watson questions the women in the Black Horse Tavern, a Salvation Army band plays "Onward Christian Soldiers" in the street. The film is set in 1888. Arthur Sullivan wrote the tune, "St. Gertrude", and published it in the December 1871 issue of the Musical Times.
When Holmes visits the Lees disguised as a chimney sweep, he removes his false mustache and false blackened nose. His real nose is still visible in the next shot, along with coal dust and soot.
The revolver Watson gives Holmes towards the end of the film is nickle-plated, not stainless steel. They look very similar in low-key monochrome coloring.
When Spivey shoves Catherine Eddowes' body out of the carriage, Hilary Sesta moves her arms to break her fall.
About 90 minutes into the film, Holmes and Watson are looking for Mary Kelly, and walk past a sign with a bell-shaped logo. After a right turn and a left turn, they walk under the same sign. The street is shown from a different angle, and dressed up with a cart to make it seem like a different block, but it's clearly the same part of the set.
Some of Holmes' laboratory equipment has nonsensical connections: The spout of a retort connects to a glass coil which then connects to the top of the cooling jacket of a reflux condenser. (In reality, only cooling water would connect to the jacket, and then it would be fed into the bottom.)
When Holmes and Watson are driving in a carriage through open landscape, shots from inside the carriage show houses through the rear window. Exterior shots of the carriage show no houses behind it.
The Jack the Ripper murders happened in 1888. Tower Bridge, which opened in 1894, is complete in several establishing shots.
Prince Albert Victor, "Eddy", was created Duke of Clarence and Avondale in 1890, two years after the film is set. His young cousin, Charles Edward, was born Duke and Earl of Clarence, but he was 4 years old in 1888. He later became Duke of Saxe-Coburg and Gotha in Germany.
Near the end of the movie, yellow parking lines are painted on the curb.
In a wide shot of London, with Westminister Bridge and St Paul's in the mist, a light-colored motor vehicle is on the bridge.
The "City of Westminster" street sign at the end of Baker Street is a Mischa Black design, introduced in 1967. It says "Great College Street", which is at the end of Barton Street, where the scenes were filmed.
In the final dialogue scene between Holmes and Watson after the Whitehall interview, Holmes uses his right hand to bow four notes on the free-standing upright violin on the desk: middle B, E, D and treble E, on open strings. It's impossible to play a B natural on an open A string; the string's pitch must be raised to B by a finger stop for the dubbed sound to be physically possible. The open string pitches are tenor G, middle D, middle A, and treble E.
When Holmes is going to the meeting in the Masonic lodge at the end, he first passes Buckingham Palace, which may have been on his way from Baker Street. He then seems to have crossed the Thames, because in the next scene he approaches Westminster Palace from the south side of the river, effectively re-crossing it.
The little girl has no provenance. Without proof, she is indistinguishable from any other little girl.
At the end of the film, when Holmes is relating the story to the Prime Minister, Holmes claims that Annie Crook married her lover without causing any concern. Her lover was supposed to be the heir presumptive to the British throne, so it would've caused cause great concern.
When Dr. Watson writes on the blackboard, he says Polly Nichols was the first victim, but the writing on the board says "victim #2."
Holmes and Watson occasionally mix up the order of the Ripper's first two murder victims.