Mrs. Hudson
Martha Louise Hudson, née Sissons (Una Stubbs) is the landlady of 221B Baker Street. Sherlock won his way into her good graces after ensuring her husband, who ran a drug cartel, was executed for a double murder in Florida.
Although she repeatedly insists that she is not their housekeeper, Mrs. Hudson fusses over Sherlock as if she were, and he takes it for granted that she will provide dinner for him. She is often horrified to see Sherlock keep human body parts in his kitchen appliances (refrigerator, microwave) for experimentation. In "A Study In Pink," upon first meeting John, Mrs. Hudson thought he was Sherlock's romantic partner, and throughout the show, she is seen to still believe that they are a gay couple, despite John's repeated protests that he is not gay and that he and Sherlock are not a couple.
Despite his impatience at her concern for him, Sherlock has shown to have a great deal of affection for Mrs. Hudson; for example while he often tells her to shut up when he considers her input an annoyance, he is quick to reprimand his brother Mycroft for attempting to do the same. In "A Scandal in Belgravia," Sherlock pushes a CIA agent out of a second-story window multiple times to punish him for torturing Mrs. Hudson; later in the same episode when John suggests Mrs. Hudson leave Baker Street for her own safety, Sherlock appears appalled at the notion and informs John 'England would fall' should such a thing happen. In "The Abominable Bride", Mrs. Hudson is shown upset that she has no speaking role in Watson's stories and Sherlock suggests he "give her some lines" as she "is perfectly capable of starving us".
It is revealed in "His Last Vow" (along with her full name) that she is a "semi-reformed alcoholic," a former "exotic dancer," and that her weakness is marijuana.