Jewel Robbery at the Grand Metropolitan

Poirot is in Brighton for his health, which is the sort of holiday that never stays a holiday for long. He is meant to be resting; the necklace has other plans for him. A theatre actress staying at the same hotel has her pearl necklace stolen, a piece worth a small fortune, and the theft happens inside a well-run establishment where nothing is supposed to go missing.

The puzzle is how the necklace vanished at all. Poirot, who would rather be doing this than resting, gathers the guests and staff around him and begins the slow business of finding the liar. Hastings is along to be useful and occasionally to be wrong, and the hotel gives the whole thing a pleasant, closed-community feel. The actress makes a fine fuss, the staff look at their shoes, and Poirot takes notes. And everyone has a room and a routine, and one of the guests has a necklace they should not have.

Anthony Horowitz and Agatha Christie wrote it, Ken Grieve directed. David Suchet is Poirot, Hugh Fraser is Hastings, Philip Jackson is Japp and Pauline Moran is Miss Lemon. Trevor Cooper plays Ed Opalsen with Sorcha Cusack as Margaret Opalsen, Karl Johnson as Saunders, Elizabeth Rider as Grace, Simon Shepherd as Andrew Hall and Hermione Norris as Celestine, whose television career was still very much ahead of her.

It is a light, elegant entry, closer to a game than a tragedy, and the seaside setting suits it. The pearls give the plot its shine, but the real pleasure is watching Poirot do his work with the sea air in his lungs. He came to Brighton to rest. What he got was a mystery, and he does not seem to mind at all. It is the kind of episode you watch with a cup of tea, and it rewards the attention the way a good conjuror does.