Producer William Sterling was keen for the second series to take its cue from the works of Alfred Hitchcock, advising his directing team to view Psycho (1960) to gauge the tone he wanted the stories to take.
What was effectively the pilot episode of the series, Sherlock Holmes: The Speckled Band (1964), originally aired as the eighth edition of the first series of Detective (1964), an anthology of popular sleuths. Following this the BBC bought the rights for two series-worth of Holmes stories from the Doyle estate.
After shooting of the two-part adaptation of The Hound of the Baskervilles ran over schedule and over budget due to persistent rain during location shooting, the second series once again fell victim to the time and money problems that plagued the first.
Douglas Wilmer was infuriated when he first received some of the scripts for the series. He said that the dialogue ranged from being acceptable to downright deplorable. As a result, the actor spent many hours into the night at home, re-typing most of the scripts. The actor stated that the officially credited writers, hadn't bothered to carry out their research, regarding the Holmes stories in general.
The 1968 episode "A Study in Scarlet" doesn't include any reference to the introduction of Sherlock Holmes and Doctor Watson, or how they came to be acquainted with one another. Instead, the episode begins with Holmes and Watson going about their usual business, plus giving the strong impression that they have known each other for years.
Douglas Wilmer later stated that the series was riddled with incompetence and the scripts often came in late. He claimed that the scriptwriters ranged from "the brilliant to the absolutely deplorable." Some of the scripts were so lacking in quality that Wilmer himself rewrote them sometimes staying up until two o'clock in the morning rewriting.
Had this third series commenced, the plan was to dramatise stories from The Exploits of Sherlock Holmes, a short story collection written by Adrian Conan Doyle and John Dickson Carr.This potential third series never came to pass.
Peter Cushing stated that the hectic schedule affected his performance: "Whenever I see some of those stories they upset me terribly, because it wasn't Peter Cushing doing his best as Sherlock Holmes - it was Peter Cushing looking relieved that he had remembered what to say and said it!"