varian, many thanks for your contributions to this thread, especially for the link to the research and to the Secret Barrister's views.
The evidence hasn't changed since I started work with offenders in the late 70's. The next 40 years I worked with children and families, most families had an adult who'd been in prison and many had children involved with the youth justice systems.
The evidence says, countries who put money and expertise into early years are likely to have less drug/alcohol/mental health or crime than those like ours, that come on after offending/anti social behaviour has started to attract the attention of the authorities.
Boris Johnsons and Priti Patel are appealing to people who aren't interested in research, or what actually works and helps society.
Short prison sentences don't work. They're often the last resort for drug addicted mothers who have worked their way through alternatives to custody. They get 3 months hmp. Unless they have family to step in, their children go into foster care, often separately as finding places for 3 - 6 children and keeping them together is almost impossible. The emotional damage done to these vulnerable family units is immeasurable, although we can predict those children will become "known" to the criminal justice system.
Put money into prevention, into early years, into supporting vulnerable parents. Bring back youth clubs, relationship building between area social work teams and the families they're there to support. Re-open the family centres, the drug and alcohol treatment services. Yes, have more police officers and teams of social workers, probation officers and community police officers working together.
By all means have long sentences for dangerous offenders. But don't think returning to Victorian bread, water and cruel regimes will rehabilitate them.
We could learn a lot from the Netherlands.