The Red Signal is the eighth episode of the television series The Agatha Christie Hour and is based on the Agatha Christie short story of the same name.


Dermot West gets these "red signals" warning him of imminent danger. He gets one of these just before a dinner with friends. The dinner concludes with a seance warning the men at the dinner not to go home for there will be blood....

Comparison with original story

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  • The adaptation is very faithful to the original story. Dermot's story about his "red signal" in Mesopotamia and Sir Alington's discourses are reproduced faithfully, at the cost of making the relevant dialogues very long drawn out. A couple of additional scenes to dramatise what is described in prose in the story:
    • At the beginning of the episode, Dermot is dressing for dinner. And he gets a "red signal" (shown by everything on the screen turning red and white). Milson is seen helping him and Dermot gives him the night off. Milson does not appear in person in the original story and is mentioned only.
    • Before the dinner, Claire is shown searching her drawers and finding a long bladed knife. Jack comes in and disarms her. Presumably this is done to cast suspicions on Claire.
    • After the death of Sir Alington, there is a scene where Johnson is interviewed by Inspector Verrall and he tells him about the argument between Sir Alington and Dermot which he overhead.
  • There is an additional scene where Inspector Verrall comes to the Grafton Galleries looking for Dermot. Jack and Claire are there and they say Dermot had just left a few minutes ago.
  • Cawley actually initiates the request for a cup of tea. He and Dermot then go to the kitchen and they chat there. Cawley remarks that he was just going off duty when he was called to accompany Inspector Verrall. Dermot suggests that Cawley make a phone call to his wife. He leaves the kitchen to make a call and Dermot takes the opportunity to escape.
  • Jack doesn't shoot himself. When he turns to see the Inspector, Dermot makes a grab for Jack's gun and makes him drop it to the floor. Jack runs to one side of the room and brandishes a knife and charges towards Claire. Dermot intercepts him. A struggle ensues and then Jack drops dead from a knife wound. Whether he stabbed himself, was stabbed accidentally in the course of the struggle or was stabbed by Dermot is not made clear.


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