From: ep. 2.3
Character name: Gregson
Reference: in this ep, you can only hear the name Gregson overlapped by other dialogue in Lestrade’s protest of his use of Sherlock to his superior, when he says “I’m not the only senior officer who’s done this; Gregson–” before he gets cut off. We never see Gregson or hear mention of him (her?) again. In fact, I have long taken Lestrade’s first name (Greg) as an Easter egg of sorts, referring to Gregson and Lestrade in one character.
In the canon, Gregson and Lestrade are two of the best of the Scotland Yarders that work with Holmes on his cases, or bring them to him. In A Study in Scarlet, Holmes describes the two as competetive “as a pair of professional beauties,” and neither of which would admit to needing or admiring Holmes for what he does for them.
Later in the canon, there are others that Holmes comes to respect, and a lovely moment in “The Six Napoleons” wherein Lestrade tells Holmes just what he thinks of him.