When Scottish Green Party co-leader Lorna Slater urges people to vote as if ‘their future depends on it’, she’s not warning the electorate about the planet’s climate crisis. Independence is what Ms Slater, a Canadian-born engineer and trapeze artist, really craves.

Scotland’s Greens may brand themselves as guardians of the environment, but observers could be forgiven for thinking their primary political purpose is to act as the Waitrose wing of the SNP.