Agatha Christie created a gallery of memorable characters for her long string of whodunits, ranging from a private investigator with a huge balding head who went under the unforgettable name of Parker Pyne, to a totally objectionable early-Yuppie couple named Tommy and Tuppence.

But of all her creations, none proved so enduring as her classic pair, the fussy Belgian detective Hercule Poirot, who featured in 40 novels, and the spinster with the rat-trap brain, Miss Marple, who bore the burden of 17 tales.

Film and television has been kind to both. Poirot has recently found his absolutely perfect screen incarnation in the television series starring David Suchet. And now we have an immaculate Miss Marple, played with distinction by Geraldine McEwan, in her richest television role since her Lucia in the delicious Mapp and Lucia.

Geraldine McEwan is simply the best Marple yet. Forget the crabby sourpuss Joan Hickson of the 1980s and 1990s. Forget even wonderful Margaret Rutherford, who gave us four blissfully comic versions of Marple in the 1960s. Fun movies, but not the real thing.

For my money Geraldine McEwan is the real thing. And the Granada Television production company has subtly updated the ambience to present a character much more dimensionally complete and complex than Agatha Christie's original. This Miss Marple has a past -- she understands from personal experience the motivations and mysteries of human life.

This episode, the first in a Granada four-drama series, is interesting as it is drawn from a novel which was adapted for both earlier Marples, Rutherford and Hickson. I can't give away the plot -- except to say that it hinges on a strange sight a friend of Miss Marple sees when her train pulls briefly alongside another. Strange thing to see -- a man violently strangling a woman, with the scene indelibly framed in the carriage-window.

No-one will hbelieve that Miss Marple's friend actually saw this shocking deed. Enter Miss Marple.....

The widescreen anamorphic transfer is not of the highest cinema-quality even though it's a very recent production. But for a television drama of this kind, it is extremely acceptable. And the basic stereo sound is clear and with maximum comprehensibility for dialogue.

There are no extras of any kind. The American edition, which presented all four mysteries in a box-set, provided a one-hour 'making of' documentary plus details of other Marple characterisations, an Agatha Christie biog and a photo-gallery.