She - let's call her Jean - has been out for some years now. She's rehabilitated, has a flat, a mortgage, a job and a partner. I was one of the friends who supported her through a bleak and discouraging time in a woman's prison.

Prison staff and governors were supportive too, for many of them know how hard prison is for women. They told me as much, and so did Jean.

Yet she is one of the minority who manage to stay out. Reoffending rates have been soaring - 64 per cent of those released in 2004 were reconvicted within two years. Something had to be done. It was.

A report by Baroness Corston in December 2006 set out a shocking catalogue of women's suffering that make radical proposals essential. She suggests closing 13 women's prisons and replacing them with a network of 150 custodial family units in city centres. There was cross-party agreement to accept her report. But the Government has now rejected its central proposal and an important social gain been scuppered either by lack of money or out of fear of an uproar from the right-wing press.

It's hard to imagine another arena of public life where the difference between men and women is as marked as it among prisoners. Women are not, on the whole, members of the criminal classes. They are basically law-abiding. Prison is certainly not one of the places where women aspire to equal treatment. The family is central to their world view and their lives revolve round it. The criminal justice system, developed in Victorian times, modelled the idea of women's prisons on the male institution, without enough thought about the differences between the sexes.

But these differences matter. First and foremost, women bear and look after children. That makes it essential that they serve their sentences within reach of their families. Yet because there are relatively few women's prisons, visitors have to travel much farther - in 2007 the average distance from home was 55 miles; about 800 women were held more than 100 miles away. Those precious visits that offer so much in emotional support are harder to make to women prisoners.

There are only 4,500 women in prison: more than half - some 3,000 - have dependent children under 18 years of age; about 1,000 have children under 5; another 1,200 have children between 5 and 10. When such women go to prison childcare falls to grandparents, foster parents or care homes. It doesn't take much imagination to see how traumatic this is for children, especially if they come from chaotic and deprived homes in the first place.

The passionate attachment to a mother, even if she is a thief or a fraudster, is a basic determinant of a young person's wellbeing. Corston reckons that 18,000 children a year are affected by what is a cruel punishment that they have done nothing to deserve.

Ah, but if a woman persists in a life of crime she must take the consequences. But more than a third of adult women in prison have no previous convictions.

Women's crimes are most often - 36 per cent - theft and handling stolen goods, crimes that may go hand in hand with the men they know who are doing the thieving and asking for a bit of help: “Pop this in the back of the wardrobe, love, until I come and get it.”

It would be naive to think that women can't be criminals in their own right. Some are thoroughly dangerous and need to be kept away from the public for a very long time. But it is interesting that the worst of all - even Myra Hindley and Rosemary West - committed their appalling crimes as the sidekicks of men. In the scramble to unlock the genetic markers for crime, it may well be that women come off better.

Women fare particularly badly in prison. They self harm, they have mental health and drug problems. When they come out, they often find that they have lost their living accommodation. These are people in need of help.

I hear that a NHS team providing support in Holloway prison was asked whether, if the women were to live in smaller family units, they would still be able to contain and treat their chaotic and wayward behaviour. The answer was a confident “yes”.

Closing prisons and treating women nearer to their homes is a small but significant reform. It is a can-do option for the Government, with no downside in terms of social impact. It is possible that Government's plans to build three mega-prisons of 2,500 places each at a cost of some £2 billion have leached away the money that could have gone to this more progressive proposal. It may be that ministers fear the punitive tendency in popular debate.

It is regrettable that real concern for women suffers in the rush to lock up more and more men.

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