Two clear messages have emerged from the major investigation which this newspaper has conducted this week into the state of women's prisons. The first is that as a nation we jail far too many women for minor offences. They would be much better dealt with in other ways.

The second is that imprisoning so many mothers is doing such harm to their children – about 17,000 of them every year, all innocent of any crime – that we risk creating an even larger generation of criminals to fill our jails in decades to come. A third of prisoners' children go on to suffer mental-health problems. Two-thirds of the boys go on to commit a crime themselves.

There are ways to break this vicious circle. The first would be unrealistically expensive at a time of austerity. It is to close several of our big women's prisons and replace them with more, smaller units in which the unproductive punishment regimes of our present system can be replaced by an approach which combines punishment with serious and effective rehabilitative strategies. If and when the public purse can afford it, this is undoubtedly the strategy which should be pursued.

In the shorter term, there is a parallel approach which could seriously reduce the size of a female prison population that is now double what it was in 1990. As we have reported, there is already in existence a network of women's centres that run an extensive range of programmes for non-violent offenders. They offer drug and alcohol treatment, anger management and sessions to develop skills to tackle parenting, debt, job and housing problems. They are cutting rates of reoffending to as low as 10 per cent. Of those who do not enjoy access to such services, as many as 62 per cent leave prison and commit another crime within 12 months.

Such punishment in the community is not at all a soft option, as our reports have shown. It needs to be massively extended. To do so would have the additional benefit of saving the Treasury huge amounts; to keep a woman in prison costs £56,000 a year; punishment in the community costs less than a quarter of that.

There are other measures that we set out today (pages 24-25) to improve the way that courts, prisons, probation services, local authorities, schools and government ministers could exercise a proper duty of care towards these children. If we do not act, we are abandoning a lost generation of children who are effectively orphaned by our criminal justice system.