The Deputy First Minister claimed the only people getting more powers by leaving the EU would be the “extreme” right-wing Tories seeking to take over at Westminster.
His warning was evidence of the SNP stepping up its Remain campaign and was in response to claims by Michael Gove that Brexit would enable Holyrood to get greater power over immigration.
His intervention follows Nicola Sturgeon’s claim that Brexit would put Scotland at the mercy of the most right-wing UK Conservative government of modern times.
Mr Swinney said: “The only people who would be empowered by a Leave vote would be the extreme wing of the Tory party – people who most certainly do not have Scotland’s best interests at heart, and people who are determined to rip up the various workers’ rights and employment protections guaranteed by the EU.
“Indeed, the Leave campaign is led by the very same people who have, at every opportunity, resisted the transfer of powers to Scotland – so their hollow offers of more powers are nothing more than a Tory con-trick.”
The approach taken by the SNP leadership was attacked by their party colleague and Leave campaigner Jim Sillars, who yesterday accused Ms Sturgeon of resorting to the “whip lash of fear”.