Could it be that the son didn't like the fact that his mother was essentially "getting away with murder" and decided to take matters into his own hands?
I loved this series the dynamic between Nicola & Sanjeev was just perfect.

Yes indeedit hinted at the horror that Claire would have to endure after "escaping" Eric.made for a very dark moment in the story: Especially when the Nurse escorts the son to see his mother saying "Oh, she is such a lucky lady to have you visiting all the time" & his reply "I'm the lucky one" Very Dark indeed.
But surely all visits to people/patients in such places are monitored?

I think the son was just a sadistic b@5tard taking advantage of her vulnerability. I don't know if she did actually kill anyone, the flashes of memory implied she did but there is room for doubt. However her fate, to live in fear of her sons visits, was a horrible place for her to end up in.

We also saw dad being kind of mean at times, and with harsh and ugly expressions earlier onlike smiling in one direction, then getting an evil look while glancing away.
Claire was signaling to the kids that something was wrong at home when she also was crying earlier and begging to leave home "to be somewhere safe." Eric was probably a bully and hit out and she couldn't articulate that.
ok but this behaviour can be explained as well by her being guilty. by covering her up he owns her & may feel she owes him big time not to mention the hatred if she indeed killed boys he loved.

I think in the end, Eric made up the whole story
Yeah after thinking about it I believe you are right. It was Eric and poor Claire after living with Eric's abuse for so long now has to live with the son's. Some people just can't win in this world. She said she thought after the accident he couldn't hurt anyone again and she just wanted to live somewhere safe.
Thanks.

"Surely they would pump him for details of the events of those three nights and look for any inconsistencies in his statement."
They had the injury details from the forensic examinations and the version he gave of her attacks already matched with what they knew and nobody else did. It was enough.

I think you're right. The only thing is I can't believe the police would fall for Eric's version of events so easily. Surely they would pump him for details of the events of those three nights and look for any inconsistencies in his statement.
It doesn't really add up that Claire would have killed the two men, it seems more likely that she would have attacked Eric. Also what were the chances of her catching him in the act? Eric also didn't explain how she killed the second victim in the middle of a London street without anyone noticing and how they transported the body (presumably in his car) all the way up to Ely and buried it in the garden without being seen and without leaving any blood.

Well, with the 11th hour reveal that the son has anger management issues could not have been inconsequential.
We saw Claire with bruises around the eye, and we presumed it was the anger issues of Eric that caused thatand probably did.
If a son gave the mom a black eye, and Eric was innocent, he would have noticed and something would have come up about that. But it was undoubtedly Eric.'
We also saw dad being kind of mean at times, and with harsh and ugly expressions earlier onlike smiling in one direction, then getting an evil look while glancing away.
Claire was signaling to the kids that something was wrong at home when she also was crying earlier and begging to leave home "to be somewhere safe." Eric was probably a bully and hit out and she couldn't articulate that.
Establishing: Eric is a violent man!
I think in the end, Eric made up the whole story about her killing the young men, to save his neck. He saw the out and took it.
He presented in the interrogation as a self-loathing gay manand back in the 60s and 70s his hatred of himself might have extended to beating up men he was attracted toescalating to killing two of them.
A self-loathing hatred of himself combined with severe anger management problems then could have produced some serious assaultshe could have had 3, 2 kills and beating up the 1 guy before he was rendered incapable after his accident.
Remember in his confession how he blithely dismissed the severe beating he gave the young man outside the pub? He dithered a bit and said lamelyoh some like it rough I heard and wellyou know.
He had to come up with a reason other than the real onehe beat up 1 and killed 2 gay men he was in a relationship with, but couldn't blame the assault on Claire, so he came up with something quickly to cover that.
The brilliance of Courtenay is if you pay attention to that amazing long close up of him delivering the storyhe kind of imbues it with JUST a smidgeon if fakeryhis story is just a touch too roteand if you watch VERY closely, you can see a sense of a story he's making up that he gives us in the subtle performance.
We watch him tell the tale of the post-partum psychosis/depression, then cleverly dither that oh, you know, she NEVER got help (police can't check it); and so he tells a story carefully incorporates reasons why it can't be followed up. It was SO carefully contrived.
Then, we're treated at the end to the sadistic son, the angry and violent son. Chip off the old block. (Hint, hint, viewers.) We can also recall that throughout, he was the son who was very quiet and always acted very meek, while the other so took care of things. Wolf. Sheep's clothing.
I think the bottom line is the writer delivering to us a mass miscarriage of justice, showing the cops just got it wrong and fell for the tale.and the viewers were given enough to see that the cops were gullible.
But we the viewers were given info we needed to realize what the police did not: Eric was guilty as sin.
A different approach in a procedural.

I thought he was angry that the media attention
This is how I understood it. But damn, he was cruel considering the father's explanation of postpartum psychosis. And how did she get those bruises? I don't remember them showing who did it and assumed it was the husband with his temper tantrums. Maybe it was the son and he inherited her mental illness.

Now I'm confused after reading your post because I don't remember anything about her abusing him. Possibly she did but I don't recall that was ever directly said. I thought he was angry that the media attention had screwed up his life - wasn't he a high profile businessman or something?