Diana Rigg is outstanding as the deranged and possessive Helena Vesey in this marvellous BBC mini-series of 1989. It is a role that, I believe, won her a British Academy Award (BAFTA). It is hard to remember anyone who managed to be so funny, scary and mesmerising than Ms Rigg as this indelible protagonist, who brings the superb dialogue to life - "Laburnum! Such a pretty tree... and so many of them!"; "Treachery, disloyalty... are the most DREADFUL of crimes. And deserve the severest punishment!"; and "Ha ha ha! HERE's Mr Tiger!". This series is sometimes repeated on Sky's UK Gold channel - make sure you see it!