The former deputy leader of the SNP has accused Nicola Sturgeon of “pretending” there will be a second referendum on Scottish independence this year.
Jim Sillars said the Scottish National Party’s leadership was misleading its members by talking up indyref2 in 2020.
In a letter to the Scottish Daily Mail, Mr Sillars said there is division within the SNP between the majority of supporters who believe there will be a vote before 2020 is over and the minority of those who do not.
Mr Sillars claims that it is the responsibility of SNP members to “convert” those who are not behind Scottish independence, rather than “marching every weekend” – a reference to recent All Under One Banner (AUOB) marches across Scotland which have attracted tens of thousands.
Scotland’s first minister Nicola Sturgeon and SNP Westminster leader Ian Blackford have been among the party leaders who say they want to see another vote soon, despite the rejection of the prime minister to devolve the necessary powers.
Mr Blackford has accused Boris Johnson of “denying democracy” for his refusal to grant a request for a section 30 order.
Mr Sillars wrote: “That 45% can march every weekend, while the Unionist majority goes shopping and remains unpersuaded.
“We in the minority know it is those shoppers we need to discuss things with, in a civilised manner, and convert.
“A longer process than a few months; and one that cannot have any worth until we know the final details of the Brexit negotiations.”
The former deputy leader also questioned if there was enough “intellectual rigour” in the arguments for another referendum.
“That quality is sadly missing, if it ever was there, in today’s SNP leadership,” he said.
“Just a few minutes’ study of the idea of an illegal referendum that scrapes past the courts (most unlikely) shows what a nonsense it is.
“The Unionist majority will take no part, so the SNP ends up with a majority of a minority. What happens then? I have yet to learn of plan B.”
SNP leaders have been pushing for another vote since the general election in December, which saw the party win 47 seats north of the border.
After laying out the “democratic case” for another referendum, Ms Sturgeon sent an official request for a Section 30 order to Westminster – which was rejected by Mr Johnson this month.
Ms Sturgeon will lead a debate on Scotland’s future on Wednesday, where the Parliament will be asked to back the mandate for another referendum, before laying out the “next steps” for Scottish independence on Friday – the day the UK is due to leave the European Union.