Joining the cast is Blake Harrison (World on Fire), who plays Sergeant Morris, with Rosie Cavaliero (Funny Woman), Amanda Drew (The Gold) and Jacob Fortune-Lloyd (The Great) appearing as guest stars. In addition, Tom Forbes (Rules of the Game), Luke Norris (Poldark), Ella Bruccoleri (Passenger) and Michael Workéyè (This is Going to Hurt) will also guest star.

The six-part series follows Gabriel Book (Gatiss), the proprietor of an antiquarian bookshop with a brilliant mind. He uses his books and erudition to help the police solve crimes: the series will focus on three cases, each taking up two episodes.

The show finds its setting in 1946 London. Next door to Book is his wife, though theirs is strictly a union of convenience, a ‘lavender marriage’ to conceal Book’s homosexuality, which was, at the time, a crime.

Among those previously announced in the cast are Polly Walker (Bridgerton), who plays Book’s wife Trottie, Joey Richardson (Renegade Nell) and Jonas Nay (Deutschland 83).

Earlier this month, Gatiss said: “To misquote Goodfellas: ‘All my life I’ve wanted to be a detective!’ I couldn't be more excited to be bringing this series to the screen, and to plunge viewers into our intoxicating version of post-War London. It’s an under-examined time and an under-examined world and Bookish is the strange, funny and thrilling show that I've always wanted to make.”

Filming has begun in Belgium.