I read the book too. I remember I thought it very well written but I did find it depressing.
I'd obviously forgotten just how down it had made me feel. Perhaps if I had remembered, I wouldn't have been so keen to watch this drama - and recommend it to a friend. It was hardly a happy 90 minutes but Glenda Jackson portrayed this character and her plight so well, and the rest of the cast were excellent too.
Frightening though.
Glenda Jackson is an absolute marvel. Several years as an MP and then to return, at a quite advanced age, to acting. Her reviews in the role of King Lear were glowing - a remarkable achievement after so long away from acting.