Factual error: The show starts in 1901 with a woman constable working for the Metropolitan Police Service (Scotland Yard). However women didn't join the Metropolitan Police until 1919 (which is also when the first woman's police uniform was created). Prior to that, women volunteered in the Women's Police Service, but that wasn't formed until 1914.
Factual error: As the Royal Navy has its own police (including detectives), there would be no need for a civilian detective to be airlifted onto a submarine, especially to investigate a sudden death that was not originally believed to be a murder.
Suggested correction: The Royal Navy police are not equipped to handle murder; local police are usually used for more serious offences so no claim of a cover up. There are no MoD police attached to a submarine either, so in theory somebody would have to go to the boat. (However they still wouldn't risk surfacing).
Initially there is no suspicion of murder, only an unexplained sudden death. There would be absolutely no need to airlift a civilian detective aboard a top-secret submarine. It wouldn't be the first time a sudden death had occurred aboard a Royal Navy vessel.
Noisy Edge - S1-E12
Factual error: In the beginning of the episode, Charlie is stating that "there is always a solution" and "if there's any limitation it's got to be in the mathematician, not the math". Unfortunately, according to Kurt Godel's incompleteness theorems, this is not true. Simply put, there are mathematical problems that cannot be proven/solved.
Not What It Looks Like - S3-E2
Factual error: Season 3, episode 49 (Not What It Looks Like). Breaking glass with sound is possible, but would not work as depicted in the episode. First, in order to break the glass, you have to force the glass to vibrate at its natural frequency - that is, the frequency at which it would vibrate if it were tapped. Each piece of glass has its own natural frequency, depending on a range of factors including size, chemical makeup, shape, hardness, and manufacturing methods. No single frequency would shatter all the glass in the store at the same time. Finally, in order to break the glass the piece has to be closed-ended. You can't shatter a plate of glass with sound (nowhere for the sound waves to resonate). Please see http://www.madsci.org/posts/archives/feb98/887203231.Ph.r.html.
Factual error: In episode 17 there are some scenes showing sick 4400s all around the world. One of them is being carried into an ambulance car in Frankfurt, Germany. The ambulance car's number plate begins with the letters FM meaning Frankfurt am Main. The correct abbreviation for Frankfurt am Main on German number plates is F - not FM.
Factual error: The train car in which Elle and the other passengers are held hostage is supposed to be an Amtrak type long distance railroad car traveling from El Paso to Dallas, yet on the inside of the car we can see a large poster showing the Washington, DC Metro system map.
Thrill Kill - S5-E1
Factual error: When Dylan gets out of jail, a palm tree can be seen in the background behind him. This reveals that the scene was filmed in Los Angeles, not Philadelphia.
His Last Vow - S3-E4
Factual error: Sherlock takes pains to explain in detail that he will deliberately corrupt the magnetic code stripe on an access control card he intends to use to enter the elevator to the villain's penthouse, by carrying it next to an operational cell phone. (This is possible due to the low frequency magnetic field from a phone's vibration motor.) But when he actually goes to access the elevator, he simply touches his access card to the reader instead of swiping or inserting the card through a slot, which is how a magnetic stripe reader would operate. The elevator uses an RFID proximity reader, not a magnetic stripe reader - a phone wouldn't corrupt an embedded RFID tag.
Go Fight City Hall -- To the Death! - S1-E1
Factual error: When Quincy, the well-experienced doctor, uses the defibrillator to bring a just deceased man back to life, he never put some gel on the paddles in the first place. (00:15:25)
Factual error: Talking to Dresden, Bob refers to his first grimoire (a book of spells & magic). But the closed captioner, apparently unfamiliar with the term, has rendered the line, "My first Renoir," which, though amusing, makes no sense at all in the context of the conversation. (Refers to the aired version: the error was corrected on the DVD release.) (00:24:00)
Factual error: Any time FBI agents enter Mexico, they are always armed. Mexican law prohibits U.S. Agents from bringing weapons into Mexico.
I Married a Mind Reader - S1-E11
Factual error: A nitpicking mistake, but on the set of "I Married a Mind Reader", the front door is a modern steel design. Back in the 60's, front doors were almost always wood (steel doors weren't available until the 1970's or 80's), and the window design would have been larger on a 1960's fan-window wooden door.
Factual error: The bad guys are supposedly auctioning off the stolen Mona Lisa. But they and their prospective buyers aren't very art savvy. The painting is more than twice the size of Da Vinci's actual masterpiece. (00:44:50)
The Sins of the Father - S4-E9
Factual error: A character is revealed as having been hypnotised into committing murder against their will. This is not possible. (00:05:20)
Edward Mordrake: Part 1 - S4-E3
Factual error: Season 4 takes place in 1952. Elsa sings Lana Del Rey's Gods and Monsters. The lyrics say "living like Jim Morrison." Jim Morrison was not famous until 1960. He was born in 1943, which would have made him only 9 at this time.
Factual error: When she's giving the historical tour, Sarah talks about how the Puritans who settled in Point Pleasant faced hardships during their first winter there. But the first village at Point Pleasant was built in 1817, a century and a half after Puritans ceased to exist as a distinct group.
Factual error: Number 6 wakes up to find the Village deserted, but the central plaza fountain is still running - until he looks at it from the bell tower, when it's suddenly off. The Village fountains never appeared to be on timers (they were always on, day and night), and no one is there to turn the water off, yet it's somehow still off when Number 6 returns at the end.
Factual error: In the final scene where Grace Mayberry's house is raided in Trenton, NJ. a New Jersey State Trooper is wearing a badge on his chest. The NJSP has always worn a triangular shaped badge on their hats.
Cheatty Cheatty Bang Bang - S2-E3
Factual error: They are watching the BBC mini series of Pride and Prejudice and you can hear ending music, but that music is not played at all in the mini series.
Coming Home - S1-E3
Factual error: At the convalescent home, Dr. Conner asks if a lector has been to the home to give communion. Later, he describes a lector as a person who gives communion at church or to the homebound. A Eucharistic Minister or Extraordinary Minister of Holy Communion gives communion in the Catholic Church.