Sergeant Sally Donovan

Sergeant Sally Donovan is a minor character on the BBC crime drama Sherlock. She is a sergeant at Scotland yard and does not ever get on with Sherlock and has had an affair with co-worker Anderson. Sally told Watson that Sherlock was a dangerous man and that solving crimes will not be enough for him one day so he'll start commiting the crimes.

Portrayed by Vinette Robinson but originally portrayed by Zawe Ashton

History
Sergeant Donovan (Vinette Robinson) is DI Lestrade's sergeant and is usually seen with him on cases. Donovan resents Sherlock's presence at crime scenes, calling him a "freak" and warning Watson that Sherlock's a psychopath who will one day get bored of catching killers and become one himself.

In "A Study in Pink", she's involved in an affair with Anderson and in The Reichenbach Fall she is the first police officer to fall for Moriarty's deception and believe that Sherlock may be behind the recent theft and kidnapping.

In "The Sign of Three" she's onto the the Walter family, a family of bank robbers and she's investigating the case along with Lestrade. When they've finally had the family surrounded and decide to move in for the arrest, Lestrade goes to help Sherlock thus annoying her as it was the biggest case of his career.

In the un-aired pilot, Donovan is constable and played by Zawe Ashton