Jim Wallace: Faces opposition

He said the proposals, which he described as "radical and wide-ranging", would provide the quickest and least costly way of dealing with a projected rise in prisoner numbers and improving deteriorating jail conditions.

The executive's plans for the prison service would also mean the closure of Low Moss prison near Glasgow, as well as Peterhead prison in Aberdeenshire.

The Prisons Estates Review, which the executive is basing its proposals upon, has been dismissed as "fundamentally flawed" by two academics.

Professors Phil Taylor and Christine Cooper also attacked the role played by accountants PricewaterhouseCoopers, who advised the executive during the Estates Review.

However, Mr Wallace insisted the executive's figures were "robust" and dismissed the academics' report.

Mr Wallace said: "It is not enough for critics of our proposals simply to say they do not believe our figures.

Reduced staffing

"If anyone can bring forward an alternative proposal that would achieve our objectives more quickly, at the same time or at lower cost, then I would be delighted to consider it."

John McAllion, the Labour MSP for Dundee East, warned the executive it faced a backbench revolt.

He said there was "opposition across the parliament" to the proposals.

The left-winger said he believed the �700m in savings identified by the private sector would come from reduced staffing levels and poorer wages and conditions for prison staff.

Mr McAllion said: "I can't believe that, knowing the record of the private sector in prisons across the UK, the party of labour can go along with such a blatantly anti-union programme such as that."

Maureen MacMillan, a Labour regional MSP for the Highlands And Islands, admitted there were many in her party who had "grave concerns" about private prisons.

John McAllion warned of a revolt

She said: "The Labour Party does not believe that value for money equals lowest cost in wages and conditions."

She added: "Rehabilitation is as important and the Scottish Executive must ensure that the need to deliver rehabilitation programmes is paramount in their decision making."

Labour backbencher Karen Whitefield also expressed concern over the plan, saying: "I have yet to be convinced about the use of the private sector to run our prisons."

Margaret Jamieson - another Labour backbencher - said she took a "pragmatic approach" to the private prison in her constituency of Kilmarnock and Loudoun.

"I don't have a hang-up as to who owns the building," she said.

"I am however deeply concerned that staff in prisons such as Kilmarnock are outwith the public sector, without the protections and standards required of the public sector."

'Simply wrong'

Scottish National Party justice spokeswoman Roseanna Cunningham said: "As a lawyer and as a politician, I know that the prison estate is in need of an overhaul.

"The state of some of our prisons is indeed shocking. But the programme of closures and privatisation that the executive proposes is simply wrong."

SNP backbencher Alex Neil suggested the estate review and the figures on which it was based were "fairytale nonsense".

He said: "PricewaterhouseCoopers are to the prison service what Arthur Andersen is to Enron.

"In other words, they took the figures they were given, there was no audit, no independent assessment of the figures, and the whole thing is fairytale nonsense."

However, the SNP motion attacking privatisation of Scotland's prisons was defeated by 76 votes to 28.

Mr Wallace's motion welcoming the publication of the consultation paper on the future of the prison service was passed by 78 votes to three, with 26 abstentions.