The battle, not just between the parties but the forces of nationalism and unionism, is often depicted as a roughly 50-50 contest between two fierce and solid tribes. In truth, the boundaries have always been porous, and new research for the Tony Blair Institute finds them more porous than ever. The SNP is facing a greater threat than at any time in its 16 years in charge at Holyrood.

Overall, a picture emerges of a three-way division in the Scottish electorate: 25-30 per cent of fervent nationalists for whom independence matters more than anything else; a similar number of committed unionists; and 40-50 per cent in between: voters with views about Scotland’s constitutional future, but who now care more about day-to-day matters like healthcare, education, jobs and prices.

That view is on the wane. It’s not that support for independence has declined: Scotland remains a 50-50 country. But, for many Scots, independence is now a long-term dream rather than an immediate necessity. For now, other questions matter more, and fewer voters think the SNP has all the answers. The Rutherglen result means that Scottish Labour has clawed its way back to first base. For the first time in nine years, it is once again relevant.

Want to see more SNP fails? – Health Matters