At first sight the colossal success of Poirot is difficult to explain. The Agatha Chrisitie world of detection is long gone , the new kids on the block are the edgy Sarah Lund in The Killing and Captain Berthault in The Spiral. Softie Grabol has defined a whole new genre with her trademark knitted fair isle sweater, lonely lifestyle and questioning eyes whilst Caroline Proust is following her as someone always on the verge of breakdown. It’s quite different to the safe middle class world of Christie where little villages have more murders than downtown Joburg and incompetent detectives need the help of Poirot or Marple to solve them
You could say Sherlock Holmes is dated too, but the recent interpretations of Robert Downey and Benedict Cumbernatch are quite different from the classic Basil Rathbone with his aquiline profile, deerslalker hat and meerschaum,
The answer surely lies in the brilliant representation of David Suchet. He has remained faithful to the mannerisms , the conceit, the dandiness of the Belgian detective but built on it too with his own interpretation. The culmination is still a room where Poirot reveals all to the cast , though not in this final episode, and the story is very much recognisable if you have read the book
This last episode was based on The Mysterious Affair at Styles, one of the cleverer Christie’s as murders are committed by auto suggestion. At two hours it was on the long side and I will admit to dozing off. Poirot now was on his last legs confined to a wheel chair but still capable of working out the murderer. The supporting cast was able enough but Agatha Christie does not create that many three dimensional characters. Hugh Fraser was a convincing Hastings. The final part was somewhat improbable but belief is best suspended anyway.
Whatever we reviewers say there are simply programmes that attract a faithful audience. One such was Hawaii 5 0 and another is Poirot.