Benedict Cumberbatch claimed that his character of Christopher Tietjen was one of the more admirable he has ever played. He claimed "[Christopher] has many admirable qualities I'd like to siphon off into my life."
The series covers the women's suffrage movement during 1914. Anne-Marie Duff who plays Edith Duchemine, played a dedicated feminist activist in Suffragette (2015)
Reunites Benedict Cumberbatch and Roger Allam, who previously starred together in BBC Radio 4 sitcom Cabin Pressure.
Both Benedict Cumberbatch and Rupert Everett have played Sherlock Holmes- Cumberbatch in Sherlock (2010) and Everett in Sherlock Holmes ed il caso della calza di seta (2004).
Rupert Everett's introduction scene in Episode 3 as Mark Teitjens is a scene where the gentleman across from mentions an "Algy Hyde" from the paper and Rupert Everett has previously played Algernon, "Algy", in the Importance of Being Earnest film (2002).