ALEX Salmond's new book will be like a "volcanic eruption" for the SNP which may need to be replaced by a new independence party, according to its former deputy leader.

The Herald reported that Jim Sillars said Alex Salmond’s recent trial and acquittal had shown there was a need “for a complete clear-out of the highest levels of the party before it is again fit to lead again”.

The extent of this “rot” could require the independence movement “to set up something new, untainted, in its place”, he said.

Salmond was cleared of 13 sexual assault charges at the High Court in Edinburgh last month, and suggested he had been the victim of a politically-motivated conspiracy.

Senior MPs in the party have hit out at the way the case was handled and have called for Salmond to rejoin.

READ MORE: SNP MPs call for resignations after Salmond verdict

In the forthcoming issue of the Scottish Left Review, Sillars says the "trial of the SNP both at party and parliamentary level is yet to begin".

The revelations in Salmond's book about the case “will gladden Unionist hearts”, and “a tempest of scorn will sweep down on and over on the independence movement”, he adds.

Sillars was deputy to Salmond when he was SNP leader in the 1990s.

He has previously said Salmond shared information about his case with him in advance of the trial which pointed to a conspiracy against him.

Although this was not produced in court for legal reasons – the judge ruled it could lead to the trial straying off course – the former First Minister now intends to make it public in his book.

Sillars said: “The criminal trial of Alex Salmond may be over, but the trial of the SNP both at party and parliamentary level is yet to begin.

“It is unavoidable.

“The book he is writing, with the material he was not allowed to produce at trial, but which has all the authenticity of Scottish government and SNP party documents, will be like a volcano going off underneath some people. Some whose identities I and others know, but cannot name, must tremble at the prospect of what is to come.

“There could be another police investigation, this time not into Alex Salmond.”

READ MORE: The way is now clear for Alex Salmond to rejoin the SNP

He continues: “For the rest of us, it is the effect of that coming volcanic eruption on the SNP as a party, as the electoral wing of the independence movement, that matters.

“Not being in the Salmond camp, but in the SNP, and having devoted the major part of my political life to the cause of independence, I see a need for a complete clear-out of the highest levels of the party before it is again fit to lead.

“The cult of personality, the obsessive desire of leaders for complete control of the membership and parliamentarians, the growth of a clique of acolytes, one-person rule – there has been a rot growing at the heart of this organisation for years.”

Sillars also suggests the SNP may no longer be fit for purpose.

He wrote: “The independence movement is not just the SNP, but the movement as a whole has much invested in the party as the instrument to achieve democratic success.

“As the rot is uncovered, the temptation – already being thought of by some - will be to set up something new, untainted, in its place.

“That might need to be done if the damage to come proves fatal. I hope not, because it is not easy to replace and fill the electoral space of a long established organisation.

“I speak from experience of an attempt to do so in the mid- to late 1970s with the Scottish Labour Party.

“It is better to cleanse a sword than to discard it, in the hope of finding another. But if the sword cannot be cleansed enough … well … we shall see.

“There is enormous strength, and ability, in the independence movement.

“Whatever direction is taken, it will eventually succeed.”

The SNP have been approached for comment.