Cushing was an aficionado of Sherlock Holmes and brought his knowledge to the project. He reread the stories, made detailed notes in his script and sought to portray Holmes closer to his literary counterpart. It was Cushing's suggestion that the mantlepiece feature Holmes' correspondence transfixed to it with a jackknife as per the original stories. However, when producer Anthony Hinds suggested excluding the famous deerstalker Cushing objected, saying Holmes' headgear and pipes would be expected by the audience. Cushing scrutinised the costumes and screenwriter Peter Bryan's script, often altering words or phrases. Lee later claimed to be awestruck by Cushing's ability to incorporate many different props and actions into his performance simultaneously, whether reading, smoking a pipe, drinking whiskey, filing through papers or other things while portraying Holmes. Morell was particularly keen that his portrayal of Watson should be closer to that originally depicted in Conan Doyle's stories, and away from the bumbling stereotype established by Nigel Bruce's interpretation of the role.