The number of women in prisons has more than doubled in six years, it was revealed yesterday.

The astonishing increase has caused the Home Office to announce a new think-tank to consider how female interests can be better represented in the criminal justice system.

But prison reform groups called for the abolition of women's jails. In 1993 there were an average of

1 560 women in prison, but by 1999 this had increased to 3,250, according to a Home Office report on women and the criminal justice system.

The number of men in jail also rose sharply - up to 61,500 in 1999, a rise of 43 per cent since 1993.

But the increase among women prisoners caused greatest concern.

They made up 3.5 per cent of the prison population in 1993. By 1999 that had risen to 5 per cent.

Home Office Minister Charles Clarke admitted that the rising population indicated inequalities in the system.

`We need to take account of women's interests if we are to provide an effective and efficient system that is fair to all,' he said. `Research shows provision of safe and secure accommodation for women pre- and post-trial is patchy. There is also evidence that lack of knowledge about child care provisions may exclude women from consideration for a community sentence.

`We need to investigate these types of inequalities and look at ways of providing better provision for the future.'

A Home Office spokesman added that officials were also in talks with the Fawcett Society a voluntary group which campaigns for equality between men and women, about how to take better account of women's interests in the criminal justice system.

But Frances Crook, of the Howard League for Penal Reform, called for the abolition of women's prisons.

She said: `Women haven't got worse, the system has got more punitive towards them.

`In the 90s, women on the edge were portrayed as feckless and there was media coverage about girl gangs which whipped up an anti-women feeling in the system.

`By the time women get to court, they don't get much sympathy. But they should be treated differently from men, particularly if they have young children.

`Offences like shoplifting are, of course a nuisance but it won't be solved by locking women away in prison. We would like to see all women's prisons closed down.'

The figures show that the proportion of known women offenders remained steady at 17 per cent of the female prison population.

Women were also less likely than men to have offended in the last year.

They tended to have shorter criminal histories than men and were more likely to be arrested for less serious offences, such as shoplifting. The most common offences for women inmates were theft and handling.

This year more than 40 per cent of sentenced women prisoners and more than 50 per cent of women in jail awaiting trial have reported being dependent on drugs in the 12 months before coming to prison.

Only 25 per cent of released female prisoners had found jobs when interviewed five to nine months after discharge.

In 1999 ethnic minority groups made up 25 per cent of the female prison population Eighteen per cent of male inmates were from ethnic minorities.