Halfway through the second series of the BBC series Parole (a documentary series dealing with two parole hearings in each episode - available on IPlayer).
The thing (like the first series) it really cements is the damaged character of the people who end up in prison; almost without exception they have experienced traumatic & chaotic childhoods... this is not to deny they are responsible for their actions, but it helps explain how they find themselves breaking the law
I used to do voluntary work for NACRO when it was just for people on probation, etc. Teaching basic reading and arithmetic to people who'd been failed at school then gone into petty crime when they had no other future.
Things have not improved.