The Scottish Nationalists claim they will pull the strings if Sir Keir Starmer falls short of an overall majority at next year’s General Election.
Their EU Accession spokesman Alyn Smith said: “The SNP could hold the balance of power.
“We’d use our influence to undo Brexit as far as possible and demand the UK has a close relationship with the EU.”
Mr Smith predicted: “The SNP could force a minority Labour government to rejoin the EU single market, reintroduce free movement and transfer power for an independence referendum to Edinburgh — so Scotland can regain our place in Europe.”
Last month, The Sun reported that Scottish independence backers were deserting SNP for Labour.
The Strathclyde University politics professor told The Scottish Sun on Sunday: “The crucial thing going on is that this is happening despite the fact that support for independence is not falling.
“The SNP’s problem is that they’re no longer commanding the support of Yes voters to the degree they’ve done at recent elections.”
Although Nats support has recently slumped, backing for indy has remained steady at around 48 per cent.