Tim Sherrington is an MI6 Agent and is the handler of Mycroft Holmes.
|After Joan Watson and Mycroft are saved from being killed by Le Milieu, Mycroft brings Sherlock to meet Sherrington. As payment for saving Watson he wants Sherlock to solve a case. A former MI6 analyst, Arthur West, was murdered even though he was retired. Sherrington wants Sherlock to look into the case since the NYPD has it. Sherlock reports back that West had something stolen from his apartment, had tattooed his arms and, that his arms were cut off and stolen while he was in the Morgue. Sherlock discovers that West's arms held the locations that a mole in MI6 visited and tells Sherrington. He's surprised and asks Holmes to join MI6 which Sherlock turns down and wishes him luck with the mole hunt. Later, Sherlock learns the handgun used to kill West has turned up with Mycroft's fingerprints on it. Sherlock realized Mycroft is being framed for West's murder. Sherlock calls Sherrington and says he knows who the mole is. ("Art in the Blood")
|After Sherlock hides Mycroft, he meets with Sherrington and MI6. They won't give him Mycroft's files but he indicates that if he "finds" Mycroft, he'll inform them. Holmes deduces that the tattoos on West's arm indicate dates and places the mole gave information to a source in NYC. Watson deduces that Sherrington and Mycroft's travels matched the info and Sherrington is the mole. Sherlock lies to Sherrington when he calls for an update that Mycroft made a money transfer to fund his escape. Sherrington comes to The Brownstone when Watson is alone and threatens to blind her unless she tell him Mycroft's location. Watson has prepared for this and has Everyone watching on the media room's monitors so Sherrington makes another threat and leaves.
|Mycroft surprises Sherrington eating at a pub and discretely points a gun at him. Sherrington insincerely apologizes and admits to treason because he wasn't promoted. He says if he's killed that a letter will be mailed to Le Milieu detailing Mycroft's role in their downfall and that Sherlock and Watson will be likely targets as well. He offers to take Mycroft somewhere quiet and kill him. Holmes discovers the man Sherrington was giving secrets to, Julien Afhkami, committed murder which he is able to prove. Afhkami admits to all dealings with Sherrington which clears Mycroft. Later at the 11th Precinct, Detective Bell tells Sherlock a body is in the Morgue. It's Sherrington so Gregson puts out a new Wanted message for Mycroft. However, Le Milieu killed Sherrington after Mycroft talked to the NSA and they in turn let Le Milieu know how Sherrington had compromised them. ("The Grand Experiment")|