Stop locking people up unless they are a physical danger to the public and embed long-term policies that aim to address endemic socio-economic structural inequalities that are the root cause of a lot of crime. Stop criminalising poverty. Educate young lawbreakers instead of institutionalising them.
What should we do about prison over-crowding? At a conference a few years ago I was told that in Norway once convicted you don’t necessarily go to prison right away: you often have to wait for a place to come up, like you wait for an operation in the NHS. It’s a fascinatingly different perspective.