This article appears as part of the Unspun: Scottish Politics newsletter.

The one thing becoming clear about Operation Branchform is that it looks set to cast a very dark shadow over the SNP's general election campaign.

Towards the end of last year, there was some hope among SNP folk I spoke to that the long running investigation into their party's finances may soon be over and that the party could begin to draw a line under the episode and head towards polling day unencumbered by the probe.

However, looking back now, it seems that may have been rather naive thinking.

We're just weeks away from it being 12 months on from the unexpected and dramatic day when officers searched the home of former first minister Nicola Sturgeon and her husband Peter Murrell, setting up an evidence tent in their front garden. The force also carried out searches of the SNP's headquarters in Edinburgh on the same day.

Mr Murrell, the SNP's former chief executive, was arrested on day of the searches, while the party's then treasurer Colin Beattie was arrested later that month. Ms Sturgeon was arrested in June. All three were released without charge pending further inquiries. Ms Sturgeon insisted to reporters she was "innocent of any wrongdoing".

Yet almost 12 months on from the first arrests Police Scotland have yet to send their report on the inquiry, launched in July 2021, to the Crown Office.

It's not known when the force will do so and when they do, how long the Crown Office will deliberate on the findings before deciding whether any charges will be brought against anyone or not.

Certainly, Sir Iain Livingstone, the force's former chief constable, was not about to enlighten me over the timescale of the investigation when I interviewed him yesterday.

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Asked if he thought the inquiry would end soon, he said: "I can't comment on that".

It was interesting though, I thought, that Sir Iain did make clear he was there as a sounding board for his successor Jo Farrell "on a private and confidential basis" should she want to talk things over with him.

The problem for the SNP is that with hints from UK Government figures that the general election may be just over six months away, in October, there are no signs of Operation Branchform and its fallout going away anytime soon.

There are three possible main scenarios ahead. None suggest the inquiry will be fading into the background of the public's consciousness come the autumn.

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The first is that by polling day the investigation is still ongoing, or that Police Scotland has handed its report to the Crown Office and deliberations are taking place but no decision reached.

The second is that the Crown Office has brought charges, the third is that the Crown Office decides that no charges are to be brought.

The first scenario will mean that the current news cycle surrounding the probe will continue, with the probe hitting the headlines fairly regularly when any development surrounding it takes place.

The second will mean reporting restrictions would be in place with prosecutions to take place, while the third scenario would mean that no one is facing charges and there are no prosecutions pending.

However, the problem for the SNP, it would seem, is that even if it is the third scenario that comes about, the saga of Operation Branchform will not have been laid to rest.

Back in May last year, Murray Foote, the SNP's current chief executive, who at the time had recently stepped down as the party's communications chief at Holyrood, outlined his opinions on the inquiry.

The former Daily Record editor described the sight of forensic tents outside of the home of the former first minister as "extraordinary" and a "grotesque circus" and went on to compare the investigation with the Rangers case, where more than £50m in compensation was paid out after several people involved in the administration and acquisition of the football club were wrongly prosecuted.

"The authorities have previous for high-profile inquiries collapsing in scandal. If they have spectacularly misjudged this one too, then the reputational cost will be far more substantial than the cash spent on manpower,” he wrote.

The Herald: Murray Foote, current SNP chief executive, described the forensic tents outside of Nicola Sturgeon's home as a 'grotesque circus'Murray Foote, current SNP chief executive, described the forensic tents outside of Nicola Sturgeon's home as a 'grotesque circus' (Image: Newsquest)
"I'm not saying Branchform is a wild goose chase – but what if it is? Surely it's worth considering.

"Actually, if we cherish the presumption of innocence, then a no charges outcome must be at least considered. And the fallout would have serious consequences for the investigating authorities."

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The problem for the SNP is that even if what would be regarded as the best scenario for the party does come about – no charges – it would be a big risk for the party to go on the warpath against the investigating authorities.

Many voters facing their own struggles with the cost of living crisis, may be in no mood to find much sympathy for a party of government fighting to settle scores rather than working to deliver policies that may ease the daily difficulties for millions of Scots.