Fracking has long been a troublesome issue for the SNP; thanks to scathing comments from a former Government adviser, it just got even more so.

The party’s position on whether the controversial process of unconventional oil and gas extraction should be allowed in Scotland has been both confusing and misleading for some time, of course.

Back in early 2015, when energy minister Fergus Ewing announced a moratorium, it was presented to business and the public as a chance for independent experts to examine scientific evidence and report back on any environmental and safety concerns. Many thought this a rather cynical attempt to kick the entire issue into the long grass, but Mr Ewing insisted any future decisions would be transparent and evidence-based.

During the recent election campaign, however, SNP leader Nicola Sturgeon appeared to pre-empt the evidence by making it known she was “highly sceptical” about fracking. She went even further by suggesting research had been ordered that would undermine the case for it.

According to Professor Paul Younger, who was part of a panel that has already told the Scottish Government shale gas could be safely and profitably extracted, Ms Sturgeon has cynically hardened her stance for electoral purposes – many SNP supporters as well as the Greens, Labour and the LibDems are against fracking – and had “taken flight from reason”.

The leading Glasgow University academic also says the case for Scottish independence could be damaged by such a stance, with the country left reliant on Russian oil and gas imports.

So, what are we to make of this latest development? Well, Professor Younger is a leading expert in the field and his accusation the First Minister-elect is prepared to ignore scientific evidence in order to avoid taking an unpopular decision is both serious and concerning.

With this in mind, it is surely time for Ms Sturgeon to come clean about her party’s position: is fracking to be part of Scotland’s energy mix or not?

Regardless of which way it eventually goes, the SNP has some serious questions to answer, not least around what is starting to look like an intentionally expensive and lengthy process that is losing integrity by the day.

This is a high-stakes debate, of course, and it has left Ms Sturgeon in a tricky position.

On one side, we have Ineos, owners of Grangemouth, confident that fracking offers a safe, cheap energy future for Scotland – as well as skilled jobs – at a time when Scotland’s oil and gas sector is in trouble.

On the other, we have a potentially unpopular policy and, crucially, Green MSPs whom the SNP may need to rely on to get their programme through parliament.

This issue may well turn into Ms Sturgeon’s first big test of the new session. But confront it she must, for the sake of the country. If she is morally opposed to fracking, she must say so. If not, she and her government must base their decision on scientific evidence and the balancing and managing of risk.

It’s time for Ms Sturgeon to give straight answers on fracking and stand by her convictions – whatever they may be.