The lack of action in the lengthy investigation into the SNP’s finances could lead to "perceptions of cover-up,” a group of senior lawyers has warned. 

Kevin Drummond KC and Douglas Cusine, both former sheriffs, said there were questions for the Crown Office and Procurator Fiscal Service (COPFS) over the “protracted period of time” taken by the probe. 

Operation Branchform launched in July 2021 after complaints that £660,000 raised by the party for a second independence referendum was spent on other things.

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Former first minister and SNP leader Nicola Sturgeon, her husband the former SNP chief executive Peter Murrell, and the former SNP treasurer Colin Beattie have all been arrested and questioned.

They were all released without charge pending further investigation.

Officers searched and removed material from SNP HQ in Edinburgh and the former first minister’s house.

A luxury campervan, parked in the driveway of the Fife home of Mr Murrell’s elderly mother has also been seized. 

Mr Drummond and Mr Cusine, who are part of a group of senior lawyers, called Quis told The Times that they believed the delay was likely because of prosecutors rather than detectives. 

They said: “The Crown is likely to have been kept up to date with the nature of the inquiry. If that is correct it can only be conjectured that either the Crown has instructed further investigation of elements of that report, or the delay is not on the part of the police but on the part of the Crown.

“Either way, the public has a right to be informed about a matter which is of such national significance.”

The lawyers said the “continuing delay in apparent progress casts an unfavourable light on the investigative process.”

They added: “In the absence of any explanation by Police Scotland or the Crown Office, the delay in such a high profile case is capable of stimulating perceptions of cover-up.

“For that reason alone, it can be said that the Crown Office should offer a public explanation for the lack of progress.”

A Crown Office spokesperson said police had not yet submitted a report.

They added: “Senior professional prosecutors from COPFS and an advocate depute are working with police on this ongoing investigation.

“It is standard practice that any case regarding politicians is dealt with by prosecutors without the involvement of the law officers. All Scotland’s prosecutors act independently of political interference.

“The duration of any investigation will vary depending on its individual circumstances. As is routine, to protect the integrity of ongoing investigations, we do not comment in detail on their conduct.”

READ MORE: Police probe into SNP finances has 'moved beyond' initial complaint

Meanwhile, Sean Clerkin, whose complaint triggered the investigation said police were “dragging their heels.” 

He told the Daily Record: “It's been going on two-and-a-half years. It was March 26, 2021 when I made the initial complaint.

"They have arrested three people and not charged them.

"The police have been very slow in their investigation. It just seems to have fallen completely silent and there is no transparency.

"They're not telling anyone anything."

The SNP said they would not comment on a live police inquiry.

Police Scotland has been approached for comment.

In July, the then chief constable, Sir Iain Livingstone, in one of his final interviews, defended the length of time taken by the probe.  

He told the BBC: “Investigations into the finances of an organisation, the finances of an individual, are often complex.

“Investigations around fraud or investigations around potential embezzlement or investigations around the misuse of funds take time. 

“You need to go and obtain information from banks and other financial institutions. We can't just do that automatically. 

“We need to go and seek judicial warrants for that. There needs to be a process around that.

“So the time that's been taken, in my judgement, is absolutely necessary.

“There's been a prudent, thorough and proportionate investigation carried out. I have been aware of this investigation since the outset. 

“It has got a dedicated team of specialists who are involved in it and they are working very closely with our prosecutors, the Crown Office in Scotland, in terms of the steps that are taken. 

“What I would say is that had we not carried out this investigation in the manner we have, I would rightly have been accused of a significant dereliction and neglect of duty. 

“That's not the case. We've done the right thing. The rule of law and the interests of justice must prevail.”