It’s honestly not your fault for using that phrase- it’s trotted out in the media all the time!
It’s just approaching the problem from the wrong angle.
If the same money was spent on community orders, strengthening the probation service, providing rehabilitation, then virtually all academic /critical thinking on the issue points to this having a good impact on crime rates and reoffending rates in particular.
Most people in prison are not first time offenders.
If you stop people from becoming first time offenders, then you stop a cycle of reoffending.
How do you stop people from becoming first time offenders? All research shows that it is down to socio-economic factors. Things are going to get worse before they get better, given the political climate in which we exist at the moment. I find knife carrying among teenagers, in the same way as they’d carry a mobile, particularly fucking terrifying, like an epidemic- locking them up isn’t going to stop this.