5. The Taxi Driver
In order for the BBC's adaptation of Sherlock to be a success it really had to impress with the lengthy pilot episode and it certainly hit the ground running. The first hour of A Study in Pink, based on Arthur Conan Doyle's first Holmes story A Study in Scarlet, introduces us to the characters of Holmes and Watson in emphatic style. But it is not until the introduction of Phillip Davis' taxi driver that the episode really gets into gear. Our first glimpse of the killer comes around an hour into the episode, when he stalks up the stairs of 221B Baker Street with his face shrouded in shadow. From there he continues to pose an intriguing threat to Sherlock, as we are introduced to his chilling game of chance that instigates the suicides. Whilst the inclusion of the gun to force his victims to take the pills feels a little forced, the Taxi Driver may be the one adversary who would have beaten Sherlock Homes and so he certainly makes this list.