During rehearsals for "Sexton Blake v. The Organisation" in 1968, Laurence Payne lost the sight in his left eye following a mishap during a rapier swordfight scene with Basil Henson.
Despite the effort and sacrifices that went into making this series, only The Find The Lady Affair: Part 1 - The Lady Vanishes (1967) (the first episode) is known to survive. The entire remainder of the run - 49 editions - remains lost.
Actress Wendy Hall nearly drowned in a boat chase scene that went wrong where she got dragged into the water in her period costume.
Pedro, Blake's trusty hound, became famous for acting as Henry in Chunky dog food commercials with Clement Freud.