Britain's senior female judge will make an impassioned plea today for fewer women to be jailed, protesting that both courts and the prison system discriminate against them.
Baroness Hale of Richmond will point to the "disproportionate increase" in the numbers of women and teenage girls in custody and call for judges to consider alternative community sentences for female offenders.
She will also complain that recent changes by the Government to sentencing rules could have had the perverse result of more women being sent to prison.
About 4,600 women are currently locked up, 6 per cent of the prison population, compared with 900 in 1960, when they represented just 3.3 per cent of prisoners. Another 267 girls under 18 are in custody. The chance of a woman being jailed by a crown court has doubled in the past 15 years.
Delivering the Longford Lecture, sponsored by The Independent, Lady Hale, the only female law lord, will denounce "some very unequal treatment" faced by women and girls who appear before the courts. "A male-ordered world has applied to them its perceptions of the appropriate treatment for male offenders," she will say. More and more in recent years, women and girls have been punished in the same way as men and boys. There seems to be less and less understanding of the ways in which their lives are very different from men's."
She will argue that courts do not pay sufficient attention to the fact that many female offenders have been victims of crime, including sex abuse or domestic violence, which could account for "behavioural problems and antisocial activity".
They suffer higher levels of mental illness and even more serious problems with drug addiction than male prisoners. The suicide rate for women in prison (there were 13 cases last year) is double that for men.
Because there are few women's jails, prisoners are often separated from their families by long distances or are housed in institutions designed for men.
"As the chief inspector [of prisons] has put it, prisons are geared to young adult males. That is their comfort zone. Everyone else is in a minority and they struggle to know how to cope."
Lady Hale will conclude that the most effective way to tackle the problem is to develop alternatives to jail: "The greatest impact would be if there were more community treatment facilities for women with mental health and substance abuse problems and more community sentences designed with women's needs in mind."
That approach has been backed in a recent public opinion poll, she will argue, but instead, prison chiefs are building two more jails for women, which has caused some to "doubt where the service sees the future".
Lady Hale will also say that the Criminal Justice Act of 2003 could have increased the chances of women being jailed because it toughens the severity of sentences imposed on repeat, low-level offenders such as shoplifters. And new sentences that combine prison and community punishments, brought in under the Act, are imposed on women who might otherwise have received community sentences. "It is right that the judiciary should jealously guard its independence from Government and the executive," Lady Hale will say. "But that does not mean it should ignore the concerns expressed by others about the trends for which its decisions are responsible.
A review of the treatment of female inmates has been ordered by ministers after an investigation into suicides concluded too many vulnerable women were being locked up. Stephen Shaw, the prisons ombudsman, warned that jailing women with drug and mental health problems was "disproprotionate and ineffective".