Cedric Messina had initially planned to screen Othello during season two, and had attempted to cast James Earl Jones in the part. However, the British Actors' Equity Association had written into their contract with the BBC that only British actors could appear in the series, and if Messina cast Jones, Equity threatened to strike, thus crippling the show. Messina backed down and Othello was pushed back to a later season. By the time it was produced, Jonathan Miller had taken over as producer, and he decided that the play was not about race at all, casting a white actor in the role.
For the scene where Iago asks Cassio about Bianca, Othello stands behind the open door. Most of the scene is shot from behind him, so the audience sees what he sees. However, not all the dialogue between Iago and Cassio is audible. Although this led to criticism when the episode was screened in the US, where it was assumed that the sound people simply had not done their job very well, it was actually done so as to increase subjectivity; if Othello is having difficulty hearing what they are saying, so too is the audience.