Joanna Cherry has warned the independence cause could have been killed off for a generation if the next general election had been treated as a de facto referendum as Nicola Sturgeon wanted.
Before her resignation on Wednesday, the first minister had wanted the SNP to fight the Westminster election on independence after the UK Supreme Court ruled in November that the Scottish Parliament does not have the power to hold another vote on the issue.
But a poll for the Scottish Election Study on Friday suggested the SNP would fall well short of 50% of the vote and lose nearly half its MPs at the next general election.
It puts SNP support at 38% and Labour on 35%, and, according to a seats projection, the number of SNP MPs could fall by 21 to 27.
Cherry said: “This latest poll, which suggests the SNP would lose every seat in the Central Belt except mine, is a wake-up call for the leadership hopefuls.
“Only last week the leadership of the party and their supporters were fully signed up to the idea that the next Westminster election should be a de facto referendum.
“On this opinion poll, the cause for independence would have been killed stone dead for at least a generation.”
The race to replace Nicola Sturgeon as leader of the SNP will last less than six weeks.
The party’s national executive committee has ruled that candidates have until February 24 to submit their nomination.
Voting will open between March 13 and 27, with the outcome of the contest to be made public as soon as the result is determined.
A conference scheduled for March 19 to discuss the strategy to gain independence has been postponed until May or June.
But the timetable has faced criticism that it does not give time for candidates to properly plan their campaigns and for party members to hear from the candidates.
The 2004 election contest, which saw Alex Salmond elected as leader and Nicola Sturgeon as his deputy, lasted around two and a half months.
Cherry said: “This contest is not just for the leadership of the SNP but for the leadership of the country.
“It is vital that SNP members and the public get to hear what these people have to say for themselves.
“There has been a lot of talk about an open debate and I don’t see how that can be facilitated without televised hustings.”
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