Hercule Poirot

Hercule Poirot was a fictional Belgian detective created by Agatha Christie. He debuted in one of her first six novels. When asked why she made him a Belgian, Christie said they make such lovely buns. During her investigations of the murder of Professor Peach at Eddison Manor, she quoted her character when she said "Use the little grey cells," a reference the Tenth Doctor immediately recognised. (TV: The Unicorn and the Wasp)

The Tenth Doctor said that Hercule Poirot could solve any case by just sitting back and thinking. (PROSE: The Stone Rose)

Behind the scenes

 * Unlike fictional detectives Sherlock Holmes or Thomas Carnacki, both crossover characters who appeared in Doctor Who novels, Poirot is not public domain in the UK.
 * The Death of Art has a brief mention of Inspector Anton Jarr's early career in which he worked with a young Belgian police sergeant.
 * Dave Stone created two parody versions of Poirot. The novel Ship of Fools features Emil Dupont, the self-described greatest detective in all of Nova Belgique. Earlier he created an Andre Dupont, "world famous Euro-Cit amateur sleuth par excellence" for a Detective-Judge Armitage text story.
 * The Murder of Roger Ackroyd and Death in the Clouds are both Poirot novels named in The Unicorn in the Wasp.