Scotland’s First Minister has announced yet another plan to take Scotland independent. On Tuesday she put on her most stern face and told a press conference she would hold a referendum on Scotland leaving the UK.

This declaration is reported, south of the border and beyond, as though it is holy writ, for ostensibly understandable reasons. Sturgeon makes it sound like a real prospect and in the current context breaking up one of the main countries in the Western alliance, the nuclear armed UK, would be a big deal. So, it gets a lot of attention.