The SNP remains the most popular party in Scotland, but a Survation poll for the Daily Record found an 8.5% drop in the party’s constituency vote and a 9.7% decline in the regional vote ahead of the 2021 Scottish election.
The SNP won 63 seats in 2016, two short of an overall majority, while the independence-supporting Scottish Greens won six seats.
A seat projection from the latest poll put the SNP down 11 seats to 52, the Conservatives down two on 29, Labour up five seats to 29, the Lib Dems up five to 10 and the Scottish Greens up to nine representatives.
Such an outcome would mean even with the support of the Greens, the SNP could not rely on a pro-independence majority.
The poll of 1,000 people also looked at Westminster and found the SNP vote remains at 36% support, compared with Tories on 27% and Labour on 26%.
Election expert John Curtice told the Record: “Today’s poll underlines the potential fragility of the SNP’s position.
“Just a small swing from the party towards Labour could result in significant further erosion of their representation at Westminster.
“Anything other than the smallest drop in the party’s support at Holyrood could easily mean that there would not be a pro-independence majority in Edinburgh.”
An SNP spokesman said: “The SNP, with our record of building a better Scotland and a message of hope for the future, holds a commanding 12-point lead over the nearest opposition.
“Meanwhile, Labour can’t even outpoll a Tory party in complete meltdown - showing that only the SNP can stand up against the Tories.”
The survey also found that support for Scottish independence remains at 45%, while those in favour of remaining in the EU has increased by 3% to 66% from the 2016 referendum.
Scottish Labour MSP Neil Findlay said: “Brexit has made clear how difficult it is to leave one political and economic union. The people of Scotland are clearly unconvinced that the answer is to leave a more important one.
“Meanwhile, after 11 years of SNP government we have an economy that doesn’t work for the many and public services that are badly underfunded. On schools and hospitals, the SNP are failing on the basics that people want from a Scottish government.
“In the months to come, Scottish Labour will outline a vision of real change for our country, support for our public services and a plan to make our economy work for the many, not the few.”