One of the schizophrenic political attitudes that infects policy making is that the people who demand big tax cuts also want to see ever more prisoners banged up in jail.
As each of them costs £45,000 a year to keep (the latest figure, though I have heard senior Tories put it nearer £70,000) why should this additional burden be heaped on taxpayers unless there is a very good reason for it? And there isn't.
All the evidence is that, for most prisoners, particularly those serving short sentences, imprisonment does no good. In fact, it does harm.
Jail used to be called a school for crime. Nowadays it is also fertile ground for drug dealers, with large numbers of non-drug users becoming addicts while serving sentences.
Yesterday's Newsnight, with Jeremy Paxman conducting a debate inside prison, showed how difficult reform is going to be, even though Ken Clarke did his best to put the intelligent and practical case for reducing the jail population.
The people who really know - the governors, officers and, above all, prisoners themselves - could not have been clearer in explaining what works and what doesn't, and what the effects of imprisonment are when the main aim of penal policy should surely be to prevent crime.
However, Newsnight had wheeled in Peter Hitchens who inhabits a la-la land of makebelieve rather than the real world. And the Westminster majority - Labour as well as Conservative - are frightened to listen to the truth, preferring to cow before Hitchens and the other dangerous media eccentrics.
So, despite the courage of Ken Clarke, the prison population will grow and crime will escalate.
I blame Hitchens, Melanie Phillips and the rest of their creed.