SNP ministers have avoided a probe into their mishandling of freedom of information (FoI) requests thanks to the Liberal Democrats.

The LibDems backed the Government to see off a Scottish Labour demand for an independent review following damning criticism from the FoI watchdog earlier this month.

In return, the LibDems secured a consultation on their idea to extend FoI coverage to private contractors providing services to the public sector.

The Scottish Information Commissioner found ministers operated a secret two-tier FoI regime which made it harder for those most likely to embarrass them.

The media, MSPs and their researchers were subject to extra scrutiny, leading to delays in requests being handled, despite the law saying the FoI system should be blind.

Under pressure to have a further review, parliamentary business minister Joe FitzPatrick, who has already promised reforms, conceded the consultation to the LibDems instead.

He said: “Against a backdrop of an ever-changing public service delivery landscape, where services traditionally provided by public authorities are now being provided by the third sector or private contractors, I'm conscious there are increasing demands to look again at the scope of coverage of the legislation.”

Scottish LibDem leader Willie Rennie said the government spent about £11bn a year procuring public services with private firms, and the scale of outsourcing was growing.

He said: “It is only fair that when firms are receiving vast sums of public money, they’re open and transparent about how this is handled. The public have a right to know if the contractors running our railways and maintaining schools and hospitals are doing a good job.

"The Scottish Government needs to take FoI to the next level."

Labour said the Commissioner’s report was a “wake up call” for ministers and the fight for a thorough inquiry into government practices would go on.

MSP Rhoda Grant said: “The SNP has not just failed to recognise the seriousness of this unacceptable behaviour and properly take responsibility for it - but it has actively blocked an investigation into it. While it is welcome that there will be a consultation on the expansion of FoI in Scotland, Labour will keep up the fight to expose Nicola Sturgeon’s secret Scotland and ensure her government is transparent.”

Tory Edward Mountain said: "This Scottish Government is based on secrecy and control. “MSPs and journalists know that getting information is like drawing blood from a stone."