This is about the TV series from 2016, not the earlier action moves of the same name.
The series was inspired by the aftermath of the Jimmy Saville revelations, where we learned (in real life) that a supposed National Treasure can turn out to have been a serial sexual abuser.
But this is not a fictionalised version of the Saville story, since he died before any of his accusers were believed, nor is it an account of any of the men who were subsequently prosecuted as "proxies" for Saville to prove that the authorities had learned their lesson. Some of those men are mentioned by name in this series, as is Saville, and some of the men who were prosecuted and aquitted.
Since the central character is purely fictional, we don't know if he is guilty or innocent. That kind of turned it into a mystery, which makes you question all the things that happen as "evidence" one way or the other. In one of the flashbacks during an interview Finchley claims he sent the babysitter home in the cab he had taken home... we see the cab leaving, but we don't know if the girl is in it or if he is just sending the cab away. There are lots of other clips that could either verify or disprove his evidence, but we never quite see enough to decide until near the end.
As the story proceeds to court we do find out more and I started to shift to a definite opinion as to my preferred outcome. Which was a problem, since well before the ending I realised that there was no good ending possible. Finchley was an unpleasant man, his accusers clearly suffered, other women probably suffered just as much but didn't come forward. On the evidence presented to the court he should probably be aquitted; but on the weight of probability he was probably guilty.
I think the show found an ending which was at least believable. Overall I didn't particularly enjoy watching this, but it was sobering viewing which I think does a good job of examining the carnage caused to people's lives by sexual abuse.