Lucy Boynton deserves more than a rating of 7 for her brave portrayal of Ruth Ellis, but "A Cruel Love" suffers from a shallow screenplay by Kelly Jones. The same few facts are told over and over: that she loved David Blakely (Laurie Davidson) to a fault, that she holds herself guilty and responsible for his murder. We learn little about Ruth's early life, or her marriage, and her children are reduced to props. She got solid help from the actors Toby Stephens and Toby Jones, though why Jones chose to whisper every single line of dialog was beyond me. As for Mark Stanley playing Desmond Cusson, the man devoted to her, he barely makes an impression.
The production design by Stephen Campbell is particularly commendable for its bold, dark colors and period sets. I didn't understand how Ruth could afford the array of dresses in her wardrobe, given that she wasn't even able to afford rent, but I took it for eye candy. The series could easily have been three episodes instead of four, except for one thing: when Boynton is on the screen, all you want is more.