If there was a series that made you forget Diana Rigg was one of The Avengers. Mother Love was it. She won a BAFTA for best actress.
Rigg plays Helena Vesey who has an obsessive love for her son Kit. This is contrasted with irrational hatred for his father, her music composer ex-husband Alex.
The first episode shows Kit courting and then getting married to Angela. Of course she is not good enough for Helena. Angela is surprised that Kit is reluctant to introduce her to his mother and later having to lie about meeting Kit's father.
At the wedding, Kit's father and his family with his second wife are not in attendance. This is because Kit fears self harm from his mother.
Adapted by Andrew Davies. I remember this being a stylish thriller when it was first shown.
Rigg dominates as Helena Vesey, she is unhinged, a tightly coiled viper ready to swipe. Davies has flashbacks to an incident in Helena's childhood.
Kit should not be fearing that her mother might harm herself. It is a case of who she would harm if Helena felt betrayed.