Figures show the average female prison population in Scotland rose from 210 a day in 1999-2000 to 413 in 2008-9. The average length of sentence increased from 228 days to 271.
Researchers said there was “no evidence” more women were committing crime, that their crimes had grown more serious, or that more women were being prosecuted. At the same time, prison sentences of three months “decreased sharply”, while there was a “large increase” in sentences of between six months and two years.
Gill McIvor, professor of criminology at the University of Stirling, who co-authored the report, Understanding the Drivers of Female Imprisonment in Scotland, described the huge rise in custodial remands and sentences as a “significant concern”.
She and Professor Michele Burman, of Glasgow University, said the growth in female imprisonment was “primarily a result of sentencers” increasing tendency to impose custodial sentences for specific categories of crime”, such as drug-related offences and breach of bail, as courts became “increasingly punitive”.
Ms McIvor said: “The growth in female imprisonment in Scotland cannot be disputed. There is, however, no evidence that it has occurred because more women are entering the criminal justice system or being convicted of more serious crimes.”
She went on: “Previous research shows there aren’t adequate enough resources in the community to help women from disadvantaged backgrounds deal with issues such as drug addiction or mental health problems.
But there is doubt over what can be achieved by a short prison sentence, especially when it means separating them from their children.”
John Lamont, the Scottish Tories’ justice spokesman, said: “Sentencing is a matter for the courts, but it is important that it is applied in a consistent manner, and if this is not happening, it needs to be looked at.”
John Scott, chairman of the Howard League for Criminal Reform in Scotland, said: “We don’t want another spate of suicides like those at Cornton Vale, (women’s prison near Stirling] where women who were supposed to be in the care of the Scottish justice system killed themselves.
“The sentences they are receiving is a significant indicator that it is the judicial response which we need to be looking at. The judiciary need to be re-educated and reassess their approach.”