I'm afraid I couldn't disagree more with the previous reviewer. I found 'A Mother's Son' to be very compelling viewing. I thought Chris Lang's script was wonderful - natural-sounding dialogue, and for one hour fifty minutes of the two hours I was unsure who had actually committed the crime, so deftly did he hint at the possible guilt of first one, and then of another character.
The casting was just as good. Martin Clunes revealed acting skills I hadn't previously seen him display as Rosie's second husband, and his character, Ben, was a wonderful contrast to David, her first, superbly played by Paul McGann.
The drama focuses on the suspicions of the mother (Rosie) that her son from her first marriage may have been involved in the murder of a local schoolgirl, and her dilemma as to how best to deal with those suspicions. Hermione Norris, who plays Rosie, has a real talent for portraying women on the edge, and she uses it to its fullest extent here. Only once does Rosie completely lose her composure; the rest of the time her torment is repressed and, with increasing difficulty, held in silent check. Ms Norris, however, can do more with silence and a slight change of expression than others can do with many pages of script, and I sometimes found Rosie's anguish almost too painful to watch.
Alexander Arnold, who plays her son Jamie, is equally good, moving seamlessly from sullenness to anger and then fear, and all the time seeming to me to give a very accurate portrayal of a wayward teenager.
Yes, it isn't an all-action drama, yes, the build-up of tension is slow, but it's steady, relentless, and, I thought, very effective. Perhaps it's the kind of thoughtful, thought-PROVOKING drama that isn't likely to be wildly popular with a mass audience, but it certainly left an impression on me. Two days after watching it I was still wondering 'What would I have done?'