The Scottish National Party conference used to flit around Scotland: Dunoon, Oban, Dundee, even Rothesay have hosted it. Nowadays Perth concert hall, a glass-fronted building near what remains of the old city walls, is one of the few places large enough to hold everyone. ‘It’s got bigger,’ two white-haired women from Moray answered in unison when I asked what has changed since their first SNP conference more than three decades ago. ‘But it’s still lots of fun, especially in the evening.’