We do not need more prisons.. we need better prisons that actually work and sentences that reflect the crime not a politicians wet dream to get re-elected... Have a look at the bbc documentary Parole... the last one covered a bloke that was locked up for 17 years after first getting an IPP sentence... the ones where you can serve indefinite time if you do not satisfy the parole board... He got 2.5 years for his orginal crime and is still in prison...as his crime was committed whilst under the influence of drugs, whilst in prison he has not managed to kick the habit and be released...after 17 years they have put him on a two year wait for a special unit to treat his drug addiction...
17 years in prison and he is still a drug addict...just whose fault is that.... probably ours as we keep telling the politicians that we want more and more people locked up for longer , hence the budget goes to incarnation rather that offender management eg Mental health services.. 14% of prisons have a serious mental health condition, treatment places available 0.4% of the prison population..so that means some 13.5% of prisoners are just dumped back on the streets untreated at the end of their sentence...and we wonder why a nutter goes berserk with a knife.