Julia McKenzie's Marple is charming, wholesome and, like the script, faithful. Miss Marple, on the other hand, has rolled around the board seeking and never quite finding that Marple-shaped hole.

Finding the perfect Poirot took another 20 years. Christie looked at him steadily, saying nothing for some time (she was a rather disconcerting woman), then said, with less enthusiasm than I expected, 'Yes.' Conversation, you will have gathered, did not exactly flow. You felt that, if you patted his bald head, he would bounce. He was small and funny and his head seemed to take up an unreasonable amount of his height.

'There,' I said, with the confidence of youth, 'is your Poirot.' Robertson Hare was a star of the Aldwych farces during which he regularly lost his trousers. I was talking to Agatha Christie at some press call (almost certainly at yet another anniversary of The Mousetrap), when I saw Robertson Hare being vibrant a few feet away. Once TV had found its Poirot in David Suchet, no change seemed plausible or even possible. Watching her Miss Marple, twinkling like sequinned knickers, you were reminded of Bernard Shaw's comment on Leslie Howard playing a suave Professor Higgins: 'It's just amazing how wrong Leslie is.' This time it is Julia McKenzie wearing a plain tweedy job at a stylish angle – both of them more substantial than the last Marple, Geraldine McEwan, who was (and who wore) a flirty bit of stuff.

Miss marple a pocketful of rye