Prison, imho, should of itself be a deterrent to criminals. Of course, financial criminals should not be incarcerated....how can they pay the dosh back if they themselves end up a drain on public money?
There is no need to build more prisons. The ones we have now should be re-fitted to allow 1 person per cell....cell meaning bed, bucket for the obvious, jug for drinking water and certainly no room for tv, playstation and the like. Inmates should be under lock and key for all the time they are there other than to speak to their legal representatives, a situation that should be in some way controlled so that contraband could not be exchanged ..
Again imho opinion prison should be a punishment, the rehabilitation coming from the fact that inmates would not want to go back there. A prison should be that, and not a holiday camp where 'association' leads to the inmates controlling the wings and not the warders.
If you do the crime then you do the time.....all of it.