The Adventure of the Clapham Cook is Agatha Christie's short story about one of Poirot's early cases, and was first published in 1924.
David Suchet was recommended by Agatha Christie's family for the titular role of this series after seeing him in BBC's "Blott on the Landscape." According to an interview with Strand Magazine, Suchet actually prepared for the role of Blott by becoming the (somewhat) similar character Hercule Poirot. Suchet said, "I ploughed through most of Agatha Christie's novels about Hercule Poirot and wrote down characteristics until I had a file full of documentation of the character. And then it was my business not only to know what he was like, but to gradually become him." Not only did it win him the six-episode Blott series, but the Poirot series spanning a quarter of a century.
According to the date on The Times newspaper Poirot and his assistants peruse, this episode occurs in November of 1935.
The registration plate ALE 165 on the taxi used by Poirot, Hastings and Mrs Todd near the beginning of the episode is still in use (2020) on a 1933 Austin.
The first ever episode of the ITV television programme spanning from 1989 to 2013.