Firms building major public infrastructure projects such as the Aberdeen bypass should be covered by freedom of information laws, it has been claimed.
Liberal Democrat MSP Tavish Scott said public procurement of services was currently worth £11 billion annually, and he argued the public should be able to access more information on how this money was spent.
The Shetland representative specifically highlighted the case of the collapsed construction giant Carillion, which was one of three members of the consortium building the £745 million Aberdeen Western Peripheral Route (AWPR) until it entered liquidation earlier this year.
Mr Scott said: “Under the SNP, firms like Carillion or ScotRail have been handed multimillion pound contracts to supply the basic infrastructure that we all rely upon to go about our daily business.
“But the public are left with little recourse to uncover how taxpayers’ money is being spent and what level of performance is being achieved.
“They want to know whether the contractors maintaining our roads or running our railways and prisons are doing a good job.
“That’s why Scottish Liberal Democrats are calling for Freedom of Information laws to be extended to private bodies performing public services.
“Some of these firms are vast behemoths handling as much public money as a government department or council, so this is a crucial step to making these firms accountable to the public in return.”
The call follows a report from the information watchdog last week which found the Scottish Government’s two track practice of treating journalists’ FOI requests differently to others was “inconsistent” with the law and should end.
A Scottish Government spokesman said: “Scotland already has the most open, far-reaching freedom of information laws in the UK – we are working to widen the coverage even further and welcome all suggestions as to how that can be done.
“Legislation has previously been expanded to a range of arm’s-length-organisations providing cultural, leisure and sporting services on behalf of local authorities, private prison contractors, providers of secure accommodation to children and young people, and grant-aided and independent special schools. An order to extend FOISA to Registered Social Landlords is currently under consideration.
“We will continue to assess options to further expand coverage, and whether other private companies exercising public functions should be brought within scope.”