Since they'll be doing drugs after their release from prison anyway, why not give them a head start?
Here's the strange story of how some English prisons are actually "retoxifying" former addicts who'd been clean for years in prison:
The process, called "retoxification", is allegedly designed to boost the tolerance of former addicts who are deemed likely to start using drugs on their release, to minimise the risk of them taking an overdose. [...]
The Sun reported that the process has been ongoing in English prisons for the last five years and that more than 460 prisoners have undergone retoxification. It was already known to be in operation in Scotland.
Senior police officers were said to be furious at the news, with one saying: "We have enough difficulties coping with drug-fuelled crime without ministers sanctioning this.
"It's one of the craziest ideas from any government."