^ Oh, I didn't realise that Gregson was from the original novels. I thought he was a new character.
Gregson is one of the few Scotland Yard inspectors for whom Holmes has any regard; Holmes calls him "the smartest of the Scotland Yarders" in A Study in Scarlet
The other notable Scotland Yard inspector for whom Holmes has any respect is Stanley Hopkins, but he doesn't appear until late in the Canon.
Holmes has almost no respect for Lestrade, but Lestrade is a too thick to realize it. (See "The Six Napoleons.")