Factual error: Poirot smells and very carefully tastes a drink and says, "Potassium cyanide." It is impossible to distinguish between potassium cyanide and sodium cyanide (the other common cyanide) by this method. In addition, there are another less common cyanides that would smell and taste the same as potassium cyanide. (00:16:01)
Agatha Christie's Poirot (1989)
1 mistake in The Yellow Iris
Starring: David Suchet, Hugh Fraser, Philip Jackson, Pauline Moran
Wasps' Nest - S3-E5
[Poirot is stung by a wasp]
Hercule Poirot: The open air! It should be closed during the summer! (00:18:40)
Trivia: Poirot in the ship's lounge is reading the actual May 1st 1935 issue of Bystander (recognizable by the cover and with the correct page order, does not seem to be a simple movie prop), roughly consistent with the time frame of the first season and a contest taking place on the 14th. (00:07:50)
The Murder of Roger Ackroyd - S7-E1
Question: The doctor (James) put on a Dictaphone to make the suggestion that Roger Ackroyd was alive at 21:30 hrs. But how could he know that someone (Paton) would pass the door of Ackroyd's study at precisely that moment?