One of the Scottish independence movement’s leading thinkers has hit out at ex-First Minister Nicola Sturgeon, blaming her for a splintered Yes movement and "arrogant control of the party". 

In a visceral article written for The Herald on Sunday to mark 10 years since the referendum, Jim Sillars also criticises "sad, delusional delegates" at the SNP conference who believe John Swinney will "make the happy days come back again".

Sillars, who was the SNP’s former deputy leader and took Glasgow Govan for the party in 1988, wrote: "The Yes movement of today is not the vibrant body of ten years ago. If judged on the SNP, its electoral wing, it is lost, flat as a pancake, in a bunker of denial, heading for another hiding.

"The movement is split – SNP-ALBA – and splintered with dozens of self-created organisations working away in isolation on policies; no cross referencing, no coordination, a national movement without a national organisation.

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"How did it come to this? Step forward Nicola Sturgeon. She inherited that 45 per cent when it was still alive and kicking. She boasts of her election victories, like the 56 out of 59 seats in 2015, when the truth is that any SNP leader able to call on 45 per cent of the electorate in our Westminster system could do no other than triumph. It is what she did or didn’t do with that gifted political supremacy that explains today.

"She wasted it. The informal national Yes organisation, based on branches in every part of Scotland, was not formalised but allowed to wither and finally disappear.

"Perhaps she thought her majority, her single-person leadership, the spectacular increase in membership, and her own SNP branch system, was enough. Certainly, everything seemed to be in place for her to build the 45 per cent to a level that could not be denied a second referendum. That would have taken time, patience and policymaking subject to intellectual vigour, and another teach-in. But she didn’t build. She chose instead to become fixated on demanding an immediate referendum: the cart before the horse policy."

In his piece in today's Herald on Sunday, Mr Sillars expressed his belief that the 2014 referendum "was an interregnum" and that "the issue of Scotland’s constitutional future has still to be definitely decided".

"When that test will come, I know not. That it will come I am certain, and optimistic about the result", he added.

He also noted that one of his "grounds for optimism" is that "the unionist case for Scotland remaining in the UK is no longer viable".

"In 2014 Scots were told it was imperative for our prosperity to shelter under the umbrella of the economically powerful British state. Such a claim would be absurd now, and will remain so in future."

Mr Sillars then finished by noting that "once the Yes movement gets itself together, engages in policymaking that identifies what this energy rich small country can do to lift itself onto a different and better level economically and socially, and drives home the message, through another national teach-in, that there is no future except decline and failure in being permanently attached to England and Wales, support for independence will rise and rise, and we, from a position of growing strength will set the agenda for when the next referendum takes place."