“PRISON works,” declared Michael Howard, then the Conservative home secretary, in 1993—and few politicians from any party have dared to argue with him. As sentences have gradually ratcheted up, England and Wales have acquired the largest prison population in western Europe. The ratio of prisoners to violent crimes is now four times what it was in the mid-1990s. Ken Clarke, another Conservative, tried to reverse the trend; he was roundly attacked (including by Mr Howard, from retirement) and was turfed out of his job in 2012.

At 149 per 100,000, the incarceration rate in England and Wales is still way below America’s 707, but it is far greater than Germany’s 78 and the Netherlands’ 75. Successive governments have failed to build capacity to accommodate Her Majesty’s proliferating guests, so English and Welsh prisons are stuffed, and conditions are worsening (see article). Some are at more than 180% of their official capacity. Inspectors catalogue multiple failings—filthy cells, widespread drug use, bullying, too few opportunities for work. Suicides are rising, as are attacks on officers and riots. On July 26th prisoners in a particularly grim establishment in Nottinghamshire refused to return to their cells after lunch, and took over part of the prison.

If society were indeed made safer by banging up more and more people, then there would be reasonable grounds for doing so. But the facts suggest otherwise.

The “prison works” argument rests mainly on the self-evident truth that if criminals are locked up they are not on the streets committing crimes. And, at first glance, the figures seem to bear the argument out. The prison population has climbed by 68% since 1995 while crime has fallen by 60%.

Yet evidence from outside Britain swiftly undermines the argument. Since 2008 the number of prisoners in the Netherlands has dropped by one-quarter. Bizarrely, that country now has more guards than convicts. Even America is becoming a little less keen on throwing people behind bars. California and New York have both cut their prison populations sharply. Crime has fallen in all these places, just as it has in England and Wales, suggesting prison does not have much to do with it.

If prison does not work well, that may be because prisons are failing to turn people away from crime. Indeed, the opposite seems to be happening. Increasingly, crimes are committed by ex-cons. In 2003, 20% of people sentenced had committed 15 or more previous crimes; in 2013, 33% had.

Overcrowding is a big reason prisons are failing to rehabilitate people. Teaching people useful skills requires manpower and space. Building more prisons would relieve the crush—but slowly and expensively: a new prison in Wales will cost £212m ($360m). A country with a growing debt pile should only spend more money if it is really necessary.

There is a better alternative: imprison fewer people. The average person released from prison has been inside for nine and a half months, and research carried out by the British government shows that people serving community sentences are less likely to commit crimes than are people released from short spells in prison. At the other extreme, many sentences are too long to be useful. The number of over-60s in prison has more than doubled in the past decade.

Politicians’ reluctance to send fewer people to jail stems partly from their fear of Britain’s virulent tabloid press, which likes nothing so much as a good murder committed by a recently released prisoner. But as newspaper circulations decline, so does the red-tops’ power. This might be a good time to try a new approach.