The Cornish Mystery

Alice Pengelley arrives at Poirot's door in London with a claim that is either the gravest sort of accusation or the symptom of a troubled mind: she believes her husband is poisoning her. The claim is the kind that gets a woman called a hysteric, and Poirot is having none of it. He takes her seriously, which is the wise thing to do in this genre, and sets out for Cornwall the next day.

He arrives too late. Mrs Pengelley is dead, and the community closes ranks around the body. But the neighbours have already decided what happened, and they do not welcome a Belgian detective asking questions about local poisoning. Their loyalty to the dead woman's husband is a loyalty to the village's version of events. Freda Stanton, Jacob Radnor, Edward Pengelley the widower, Jessie Dawlish and Dr Adams: everyone has an opinion and no one has a fact. The suspicion Poirot carried down from London has become a murder investigation with a town full of alibis, and the quiet menace of the village does half the detective's work for him.

Clive Exton and Agatha Christie wrote it, Edward Bennett directed. Chloe Salaman plays Freda Stanton, John Bowler is Jacob Radnor, Jerome Willis plays Edward Pengelley, Amanda Walker is Mrs Pengelley, Tilly Vosburgh plays Jessie Dawlish and Derek Benfield is Dr Adams. David Suchet is Poirot, Hugh Fraser is Hastings, with Philip Jackson's Japp and Pauline Moran's Miss Lemon in support.

The tragedy of the episode is that the warning was real and the help came a day late. Poirot is not often beaten to the punch, and the story gets real weight from letting him be too slow for once. The villagers' closed faces are the best special effect in the piece. It is a small episode, but the small ones are where this show's heart lives.