Re: Radical Suggestion...
I'm not sure that we should look at this purely in terms of how much "enforcing the law" and "justice" costs.
I wasn't (he says, decloaking like a Klingon battle battle cruiser). As you say, we are locked in a cycle of excessive cost and no good outcome. But one major win would be decriminalising most drugs. Take out the drug baron profits that make drugs costly and drive drug users to crime, and that's a huge volume of "funding crimes" that are eliminated. That would also eliminate the minor drug distributor crime which is a disproportionate number of UK prisoners. Also, whilst the drugs barons would move on to other forms of crime, we'd probably have fewer violent turf wars and gun crime. We could require users to be registered, and their use monitored by their GP, allowing healthcare interventions; Quality of drugs could be monitored, reducing some of the load on health services from bad shit. If the regular drugs were readily available legally and cheaply, then there would also be far less of a market for the designer synthetics that are something of a problem (eg spice zombies).
Obviously the drug abusers would go on to kill themselves, but that happens already. And we permit it with alcohol, fags, so why persecute the druggies? And freed of the significant costs of a failing war on drugs, the police could attend to focusing on organised crime, or the resources put into the threadbare social care pot.