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.
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)Chitarra10
Character mistake: In the opening scene, Sherlock makes a point to correct Barry's poor grammar. But later, when talking to Watson, Sherlock uses poor grammar by saying "who's sleeping with who." It should be "who's sleeping with whom." Not a mistake Sherlock would make.Bishop73
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)
Continuity mistake: As Sherlock and Watson come out of their apartment to hail a taxi to be taken to Brixton and the scene of a murder, two extras can be seen in the shot - one crossing the road and one walking up the far side of the street. At the top of the street there are two white colored cars, but they suddenly disappear, to be replaced by a dark colored car. Also the light of the building across the road is suddenly turned on.Charlie McGee
Continuity mistake: When Sherlock goes to look out the window at John leaving (after the tiff about the head in the fridge), his dressing gown is hanging off his right shoulder, exposing his t-shirt. Next there is a wider shot of him from behind, and his dressing gown is on straight, covering both shoulders properly. Then there's another closeup and it's off the right shoulder again. (00:05:40 - 00:06:10)Aerinah
Revealing mistake: When you see Sherlock and Watson in the museum, Sherlock leaves and nearly gets shot. You see him dive behind the large statue, which moves. That's unusual for a large statue, but looking closer, you can see there are wheels attached to the base. (00:49:35)59211john