Privately-run Addiewell prison looks set to cost taxpayers almost £1 billion – more than 12 times what it cost to build.
Details of the bill for the West Lothian jail – built a decade ago under the controversial Private Finance Initiative (PFI) model – were revealed after a parliamentary question by Nationalist MSP Fulton MacGregor.
Colin McConnell, chief executive of the Scottish Prison Service, revealed that the estimated cost of the 25-year agreement with Sodexo Justice Services would be £955 million as part of a deal brokered by the then Labour and Lib Dem administration.
Mr MacGregor said: “This is an absolutely staggering revelation, showing the sheer incompetence and damaging legacy of the Labour and Lib Dem executive.
“The PFI contract for Addiewell prison was always a bad deal for the public purse, but the latest estimates revealing a bill of nearly £1bn for an £80m building will leave taxpayers paying way over the score for years to come.”
David Watson, head of policy and public affairs at Unison Scotland, said the “extortionate cost” of the project reinforced calls for a full-scale inquiry into all public-private partnership schemes.
Under PFI or PPP, contractors pay for the construction costs and then rent the finished project back to the public sector for up to 30 years.
The model used to fund public sector building projects has been criticised as an expensive drain on public money, which in the case of Edinburgh has produced substandard schools.
But the SNP abandoned the system when they came to power in 2007, establishing a scheme that caps the profits private firms are able to make.
PFI deals came under the spotlight again in April after a group of Edinburgh schools built or upgraded under the scheme were forced to close amid safety fears.
The high winds which damaged Oxgangs Primary at the start of the year led to structural concerns about the building and ultimately uncovered flaws in 17 city schools.
These then had to close for safety reasons – creating chaos for thousands of children and their parents.
And as Edinburgh’s crumbling classrooms have caused uncertainty for pupils, the disruption has resulted in increasing scrutiny of the complex and contentious financing mechanism created by the Tories and championed by Labour.
The total bill for the privately built and managed public projects in Scotland is set to climb above £36bn.
Labour and the Lib Dems declined to comment on the Addiewell figures.
But Scottish Greens justice spokesman John Finnie MSP said: “PFI has been an unmitigated disaster and one which those two former governing parties should apologise for.”