But the Nationalists came under intense pressure for abstaining on an alternative Brexit proposal from Tory MP Nick Boles that would keep the UK in the single market and customs union.
Over the weekend, the SNP was told it was flirting with a no-deal Brexit unless it backed the Boles plan. By then, however, the U-turn had already begun. Sources told The Scotsman Mr Boles began to win them over in his speech ahead of last week’s votes, by hinting at something the SNP have always been firmly refused: different migration rules for Scotland.
Under the Boles plan, the UK would join the European Economic Area, whose members are in the EU single market and participate in the free movement of people – a key SNP demand to keep Scotland’s population and economy growing. However, Article 112 of the EEA agreement provides members with an “emergency brake” to suspend rules such as free movement in case of “serious economic, societal or environmental difficulties”.
Nationalists worried the brake could be used by Westminster without consulting Edinburgh. But in his speech, Mr Boles highlighted that under Article 112 it could apply to issues of a “regional nature” – and Scotland could be left out.
The UK government opposes having different migration policies, but one Tory supporter of the “Common Market 2.0” plan said it was “theoretically possible” in future.
And Mr Boles pointed out that one Tory leadership contender, Michael Gove, said in the 2016 referendum it would be “for Scotland to decide” on migration after Brexit