We still believe that the right place to build a first class prison service is in the public sector

Derek Turner POAS

But this figure has been branded "fundamentally flawed" by a report from two Scottish academics.

STUC delegates said the concept of private prisons was "morally repugnant" and was a clear attempt to drive down the terms and conditions of public sector workers.

The policy contradicted First Minister Jack McConnell's comments on Monday when he told the meeting he did not want a two-tier workforce.

The STUC has now called for Members of the Scottish Parliament to be allowed a free vote on the future of the prison service.

Protest march

Addressing the congress, Derek Turner, general secretary of the Prison Officers' Association Scotland (POAS) condemned the plan.

Mr Turner said: "We sat here yesterday and listened to Jack McConnell say that he didn't want a two-tier workforce.

"It is clear in our minds that the attempt to privatise the Scottish Prison Service is about driving down terms and conditions of public sectors workers.

Officers are threatening action

"We still believe that prisons for profit are morally repugnant... we still believe that the right place to build a first class prison service is in the public sector.

"We do not believe that the majority of the Scottish public want a prison service fundamentally based on profit and not rehabilitation."

As well as the three new private jails, there are plans to close Peterhead jail and Low Moss prison, near Bishopbriggs in Dunbartonshire.

Prison officers say the move would mean a third of prisoners in Scotland being housed by the private sector - a higher proportion than almost anywhere else in the world.

Protest march

Meanwhile, wives of prisoners at Peterhead are planning to march through the town in protest against plans to close the jail.

They are forming an action group to speak on behalf of the workforce.

They will tell the executive that closing the jail will mean massive upheaval for the jail's staff and their families.

There have been warnings of industrial action if the executive presses ahead with the policy.