Stoke-on-Trent, Staffordshire: With summer’s great silence coming, we must enjoy the birdsong while we can – as I have done with my local conifer crooner
They used to mean crusties, hippies, all-male lineups, near riots and burning toilets. Now, from Dorset to Inverness, there’s a festival – and a costume – for everyone. What caused this boom? And is there a dark side?