LIKE the proverbial bad penny, Prestwick Airport was back in the headlines this week for all the wrong reasons.

Which was perhaps unfair given that the Audit Scotland report which generated accusations of a £40 million ministerial "cover up" was not entirely damning.

However, it has become an easy target for opposition parties seeking to pin any whiff of financial mismanagement or potential dishonesty on the SNP in an attempt to dent its apparently insurmountable lead in the run up to the General Election.

Look out for points scoring at today's FMQ's.

So, what did the report actually say?

To be fair, opponents are right to ask why parliament and the public were not informed about the £39.6 million which the Scottish Government anticipates pouring into Prestwick in the form of taxpayer-funded loans by 2021/22.

The figure was calculated in the revised business plan drawn up last May, and there has been ample opportunity to disclose it.

The sum combines the £25m already invested or announced to bankroll running costs, revamps and "repositioning" of the airport, with an additional £14.6m forecast as what might be required in the years ahead.

Of course, the Scottish Government is keen to stress that no budget has been set beyond 2015/16.

A spokesman for Transport Scotland said: "The Audit Scotland figures do not reflect the actual and budgetary provision for loan funding, but are a projection of potential loan facilities that may be required in the period to 2021/22 and is, of course, subject to revision as and when commercial activities become realised."

So, the final cost to the taxpayer could go up or down.

On the plus side for the Scottish Government, the public spending watchdog concluded that the "purchase process was reasonable, given the time constraints involved". Ministers had six weeks to prepare its business case and draw up a risk management assessment for taking over the loss-making airport for £1 from New Zealand owners, Infratil, who had failed to find a commercial buyer.

There was a lot at stake; the Government's economic analysts had concluded that the airport generated £61.6m a year to Scotland's economy and underpinned 1,810 jobs.

On the downside, the original business case predicted that £21.3m of public money would be required in the eight years to April 2022 - a figure that has ballooned by 86 per cent six months later.

Ministers will hope that other forecasts from the business case - positive cash flows by 2022/23 and an ultimate return on taxpayers' investment - prove more accurate.

But it is perhaps worrying that the revised business plan of May 2014 pre-dated Ryanair's decision to set up shop at Glasgow Airport and relocate a pile of flights to Prestwick's key rival. There are just 13 return flights a week out of Prestwick this winter, compared to 29 a year ago. That hardly eases the perception of the airport as a money pit.

The year ahead could be a turning point in its fortunes, however, with an announcement due on which shortlisted airport is to become the UK's first spaceport and Donald Trump's jetset holidaymakers expected to boost coffers en route to Turnberry.

But ministers should heed Audit Scotland's parting words: always plan the "exit strategy".