Just a few comments for you to peruse.
I work as an educator in two UK prison establishments, one is a young offenders
institute and the other a category B men’s prison.
In the YOI, most of the inmates claim to be innocent! In reality I doubt
whether there are very many.
In the men’s prison I hear very few complaints about wrong imprisonment,
though I do know of one case where an inmate was in prison waiting to stand
trial for murder and was subsequently freed.
Whilst we do occasionally hear of people serving long sentences for crimes
they didn’t commit, on the whole I think it would be fair to say that it is
quite rare in the UK.
Far and away the biggest problem in UK prisons is the inmates’ lack of basic
skills, which is probably the reason they turned to crime in the first instance.
There are many instances of poor literacy and numeracy among inmates.
I am sure that you will be able get the statistics from somewhere on the internet
but I believe that there are more than seventy per cent who are considered
to require basic skills training.
Even more lack basic social skills.
I will write to you later with some more views.