Labour is calling for an independent audit into land transactions surrounding the scrapped Glasgow airport rail link.

The party wants the Scottish Government to open the books to external scrutiny of the project, known as Garl, two months after leader Johann Lamont reignited debate on the controversial decision at Holyrood.

Transport Minister Keith Brown appears to have washed his hands of the subject which cost the taxpayer £30 million without being built, Labour claimed before a parliamentary debate.

Labour infrastructure spokesman James Kelly said: "It's time for him to own up and tell us why he either allowed this to happen or wasn't aware of what was going on, the only way to do that is to allow the books to be opened for independent scrutiny.

"The SNP were adamant that both the Edinburgh airport rail link and Garl were going to be scrapped no matter what the cost.

"But the real price that's been paid has been on the economic prosperity of our two major airports which have suffered in not having a modern, efficient transport link.

"A report into improving public transport links to Glasgow Airport was commissioned and partly paid for with Scottish Government funding, but its publication was held up because one conclusion reached was to build a rail link.

"With one hand Keith Brown's department were spending money on a report which mentions a rail link to Glasgow Airport and with the other hand they were selling off the land, at a massive cost to the public purse, which makes the rail link project impossible."

Labour asked First Minister Alex Salmond to explain how land bought for the doomed Glasgow railway was sold back to the same businessman at a £790,000 loss to the taxpayer.

Ms Lamont highlighted a deal by car-parking and commercial land firm Airlink during ill-tempered exchanges at First Minister's Questions in September.

Four parcels of land in Paisley were bought for £840,000 on behalf of the Scottish Government in 2008 to prepare for the project, Ms Lamont told Parliament.

Finance Secretary John Swinney cancelled the plan in 2009, prompting anger from Labour.

The land failed to sell at a public auction and was then bought back by Airlink chairman John McGlynn for £50,000.

Mr McGlynn reacted angrily to Labour's approach at the time.

"Everything was above board, fully transparent, in the public domain and open to scrutiny," he said in a statement.

Mr Salmond said ministers have no role in property deals and accused the Labour leader of smearing a businessman for political purposes.

A Scottish Government spokesman said: "All of the facts on the cancellation of the Glasgow Airport Rail Link (GARL), including the financial information, have been in the public domain since as far back as 2009 and 2010 - including the fact that around £176 million of public money was saved as a result of the decision.

"The Scottish Government is not permitted to hold on to surplus land and speculate on the market. It must sell the land as soon as possible and within three years, which it did, on the open market and following the guidance and principles outlined in the Scottish Public Finance Manual (SPFM)."

He added: "Since the cancellation of GARL, routes along the Paisley line have benefited from £230 million investment in rail infrastructure improvements alongside a new £430 million fleet of Class 380 trains now operating in Ayrshire and Inverclyde.

"The timetable also delivers better connections, faster journey times across all routes in Ayrshire and Inverclyde and improved connectivity. It is forecast that there will be an extra half a million rail journeys each year with all stations on the routes, including Paisley Gilmour Street, benefiting from more passengers."