Kate Donegan, governor of Cornton Vale Prison, near Stirling, said she was deeply concerned at the condition of many of the women sent to the jail.

Kate Donegan: "We need viable alternatives"

She questioned whether imprisonment was the best way to treat those with addiction or mental health problems.

The prison chief told the BBC's Good Morning Scotland programme: "We have seen, since the beginning of this year, a record number of women prisoners at Cornton Vale.

"We are regularly recording more than 200 inmates. That is something I am deeply concerned about.

Kate Donegan: "Deep concern"

"I think it is important that I am not seen to be questioning sentencing policy. What I am saying is that there should be viable alternatives to prison.

"There should be a half-way house. At the moment there are no alternatives, there is nothing in between non-custodial sentences and prison.

"When on average it costs �37,500 each year for each inmate that is a significant sum to pay."

Ms Donegan's concerns follow those expressed by the chief inspector of Scotland's prisons, Clive Fairweather, in September.

Mr Fairweather told members of the Scottish Parliament that some women at the prison were a greater danger to themselves than the public.

Cornton Vale has gained notoriety because of suicides among inmates - many of them young women on remand.

The governor urges custody alternatives

In February of last year, the prison was criticised in a report for failing to prevent the suicides of seven inmates.

Ms Donegan, who spoke at a conference in Glasgow, said it would be more appropriate to treat vulnerable female inmates with addiction and psychiatric problems in the community.

She called for viable alternatives to custody and argued that social and health workers outside the prison service should work more closely with those inside to ensure a continuity of treatment and support for women.

Minor offences

However, Ms Donegan said the population was 3% of total prisoner numbers in Scotland, making it easier to implement change.

Speaking in the Scottish Parliament, Mr Fairweather said many of the inmates of Cornton Vale were bedraggled.

He said a small number needed to be there for a long time. But each time he visited there were women who were there for minor offences.

These women were not a danger to the public - but a bigger threat to themselves while in prison.