The human rights of inmates at Scotland's only all-women jail has sparked a political dispute.

The jail's visiting committee said record numbers of prisoners are being held at Cornton Vale.

The watchdog's annual report said this had restricted the prisoners' access to sanitation facilities.

Now the Scottish National Party is claiming that the Scottish Executive has failed to deliver on pledges to reduce the numbers of women being held in Scotland's jails.

It is the kind of stress that in the past has led to suicides

Christine Graeme MSP

But the executive said the problems would be solved as a ministerial group charged with investigating the jail published its findings.

The nationalists have written to Justice Minister Jim Wallace detailing their concerns.

The visiting committee is made up of lay people appointed to ensure prisoners are being well cared for.

Its annual report said that overcrowding was now causing real problems at the prison, near Stirling.

'Harbinger of doom'

As of last Friday there were 277 women held in a jail with a capacity of 230.

Many of the inmates are being housed two to a cell - seriously restricting their access to toilets at night.

Prisoners, including those with serious medical conditions, can sometimes wait for more than an hour to be allowed to go to the toilet.

The committee said this was degrading and an abuse of the women's right to humane treatment.

The convener of the Scottish Parliament's justice committee, SNP MSP Christine Grahame, said the executive has failed to prevent a rise in the female prison population.

Dr Richard Simpson: "Early intervention"

She told BBC Scotland: "It is the kind of stress that in the past has led to suicides.

"Now I don't want to be a harbinger of doom about it, but it seems to me that the stressful circumstances there for the women and the staff - with 25% overcrowding - are the very circumstances when such an event might take place."

However, the executive said measures have been put in place which will offer alternatives to prosecution for women and treatment for those with drug problems.

Deputy justice minister, Richard Simpson, said that ministers recognised the need to tackle the prison population at Cornton Vale.

He said that a ministerial group was set up to investigate the issue.

'A duty'

"This group reported back in March this year with a number of recommendations focusing on early intervention and prevention as well as working with female offenders in prison to tackle addiction and address their offending behaviour."

The Scottish Prison Service said it was "concerned" and would do its best to resolve the situation.

An SPS spokeswoman said the issue of overcrowding was "a problem across the whole prison estate".

She said: "We have a duty to take everybody sent to us by the Scottish courts regardless of age, circumstances or anything else."

Last year the jail was praised by the chief inspector of prisons for a "quite remarkable" improvement in conditions.

Clive Fairweather said all of the criticisms in his previous report - which described conditions as "wholly inadequate and inappropriate"- had been addressed by the prison.