Continuity mistake: When Sherlock is backstage at the circus and finds the yellow spray paint, he draws a line on the mirror. In the next shot, the line he drew is completely different (and in fact is more of a squiggle). (01:07:40)
Revealing mistake: When they are watching for vases, the auction website has no proper domain. It is loaded locally from the C:\ drive. (00:55:00)
Continuity mistake: The underground car seen in the CCTV video is from the Jubilee line, but is meant to be the District Line. It's also different from the one where the heroes defuse the bomb, which is an actual District Line train (D stock). The rounded doors is the most visible proof.
Continuity mistake: After receiving the third pip. Dr. Watson turns on the television to the news. During the news segment, it states the age of Connie Price as 48. Then in the scene immediately following, DI Lestrade says she was 54.
Visible crew/equipment: When Sherlock and John get into the taxi in Baker Street (leaving to go to the scene of their first case) you can see a filming crane reflected in the back of the taxi.
Revealing mistake: While Watson and Sherlock talk about the deceased banker and the crime scene photographer takes pictures of the dead body you can see the "corpse" breathing, as the buttons on his waistcoat are moving. (00:14:50)
Other mistake: At the end of the episode, the evil Shan is texting with (most likely) Moriarity. She is sitting at a desk facing a wall and yet the laser targeting ray appears directly on her forehead, which could only come through a window directly opposite her.
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.
Continuity mistake: When Moriarty puts the gum on the glass case around the crown jewels, the gum moves between shots.
Continuity mistake: When Sherlock and Watson first get to the bank, the time for New York is 7:45, then when Sherlock is trying to find out who the message is for, the time for New York is 7:20.
Revealing mistake: Before John Watson closes the laptop, the screen displays a phone tracking website in the Chrome web browser, supposedly at Mephone.org.uk. In the URL address bar, however, "file:///C/http/mephone.org/mephone.html" is visible which is a standalone HTML file on the computer's hard drive. (01:08:35)
Revealing mistake: The banker shoots himself with a Sig 226R. When you see it lying on the bed it has a screw missing from the grip. In the first episode, Watson has a gun in his desk drawer. It is a Sig 226R also with a screw missing from the grip. Obviously they only have one prop gun.
His Last Vow - S3-E4
Other mistake: The helicopter that takes Sherlock and Watson to Magnussen's house is the same one Mycroft arrives in later. Tail number G-VGMG.
His Last Vow - S3-E4
Plot hole: Sherlock manages to convince Janine to let him into Magnussen's quarters after deceiving her into thinking he is going to propose. Several days later, she is enjoying her "revenge with profits" on Sherlock for his duplicity. Problem: There is no way she could have found out. She was out cold moments after letting Sherlock in, and Sherlock himself was shot by an assailant, which he had misidentified. Only Watson knew Sherlock's true intention, but we know he did not reveal it. The shooter and Magnussen did not know and had no opportunity to tell Janine anyway. (Plus, Magnussen's credibility is too low.) In fact, if I were the director, I wouldn't bother making up a motive for being a "grasping, opportunistic, publicity-hungry, tabloid whore" (film's own quote). Such a person loves "profits", not just "revenge with profits." (00:31:00 - 00:43:00)
The Hounds of Baskerville - S2-E2
Factual error: Sherlock finds a photo of Major Barrymore's father and says he's wearing the Distinguished Service Order. The ribbon is not that of the DSO.
Revealing mistake: In the bank where Sherlock is trying to get a view of the painting with the Chinese numbers, he backs into a pillar, which wobbles. (00:11:25)
Continuity mistake: In the opening scene when John is going to the refrigerator, a white skull can be seen on the left side of the kitchen table amongst all Sherlock's science equipment. When he closes the refrigerator door again after discovering the severed head, the skull has disappeared. As he's leaving the kitchen, the skull reappears. (00:03:25)
Continuity mistake: When Sherlock steps out of the taxi on Baker Street three extras walk by. First, it's a lady with her back to the camera, wearing a dark jacket, purse, boots and a dark curly hair. Next, the two women walking towards the camera. Notice the blonde one on the left with the pony tails, dark jacket with the multi colored cloth at the bottom, and grey pants. Fast forward to when the taxi pulls up to take Sherlock and Watson to the the crime scene. As Sherlock opens the taxi door, the same first lady with the curly hair and the blonde with the ponytail are now walking together in the same direction the blonde was walking when Sherlock arrived. (00:12:58 - 00:17:51)
Continuity mistake: Early in the episode Sherlock and Dr. Watson enter a cab in daylight for a ride to the crime scene in Brixton, which is a part of greater London. It is night when they arrive.
His Last Vow - S3-E4
Continuity mistake: In the scene in the lab where they're testing Sherlock for drugs, Sherlock stands with his arms folded, then down, then folded, then down. Molly goes to reproach him, his arms are folded. The slaps somehow happen with his arms down.
Chosen answer: That line of dialogue has never actually been spoken in any of the Sherlock episodes, during seasons 1-4. However, that line is written in someone's fan-fiction story online, where it's said by Sherlock and directed at Anderson.
Super Grover ★