Prisons are necessary. But if you consider humanity's advances, you have to concede they're a bizarrely crude form of treating human beings.
The US has had private prisons for a while and, naturally, it has led to a few issues.
Judges have been caught taking kickbacks from prison companies in exchange for locking people up.
Mandatory minimum sentences have made the US prison population far and away the largest on Earth.
The vast majority of those unfairly affected are African-American and poor. The US prison system actually makes Serco look all right.
I have a libertarian mate who says privatisation is a good idea. We just have it the wrong way around.
Pay prison companies, he reckons, for the number of their former inmates who don't go on to reoffend. Every year that a former inmate doesn't reoffend, the Government rewards the prison company with a fee.
Economically, it's cute, but it's a hard political sell.
Instead, here's an idea: perhaps we just wake up and acknowledge the only way to make the world's crudest institution even more archaic is to allow people to profit from locking other people up.