A decision to move female prisoners to a male jail in an effort to ease overcrowding has been described as "shameful" by the chief inspector of prisons.

Clive Fairweather said the move to switch about 50 inmates from Cornton Vale to Greenock was an "admission of failure".

Almost a sixth of the women currently being held at the country's only women's prison, near Stirling, are to be moved.

Greenock Prison will house the women

They will be housed under a separate regime which is being established at Greenock.

The women, who have been described by the prison service as non-vulnerable, are to occupy a hall which has been cleared of male prisoners.

The Scottish Prison Service action follows a report from lay visitors to Cornton Vale, which said the situation there was degrading and a possible abuse of human rights.

Numbers at Cornton Vale have been rising steadily to just under 300, while the jail is designed to hold 230.

Mr Fairweather said the transfer to Greenock was a "worrying" development.

Mixed environment

"What it really means is that on the one hand the SPS have got no other option now because they are so overcrowded," he told BBC Radio Scotland.

"The number of women in Cornton Vale has been going up and up and up over the last four years.

"On the other hand this is really the first move of women into a truly mixed environment."

It is an admission of failure which I hope is only temporary

Clive Fairweather

While the women would be held in a separate hall, the number of inmates involved made it the largest move of its kind.

"It really is a rather shameful thing. We all should hang our heads," said Mr Fairweather.

While there had been a slight increase in the number of serious offenders held at Cornton Vale, he said the vast majority of those in the prison were there on petty charges.

"It is an admission of failure which I hope is only temporary," he added.

Deputy justice minister Richard Simpson said the Scottish Executive was concerned about prisoner numbers in Cornton Vale.

Richard Simpson said action was planned

He said: "The number there now is quite unprecedented.

"The number on remand has gone up by 50% over the last two years and that is a matter of considerable concern to us.

"We will be bringing in, next spring or maybe early summer, the time-out facility, which will take almost a quarter of all the referrals to Cornton Vale, and we are also taking powers in the Criminal Justice Bill to alter the fine default system so that those on fine default will not go to prison."

The SPS has also made other changes to tackle overcrowding at Barlinnie and Edinburgh Prisons.

For the past month all men given short term sentences from courts in Fife have been sent to Perth rather than Edinburgh.