I’ve just watched Yusuf/Cat Stevens at Glastonbury and impressed by how many people of all ages know the lyrics to songs he wrote half a century ago. Example: when he started singing Father and Son the crowd had joined in before he’d reached the end of the first word.

And the sight of tens of thousands of mostly white, middle-class fans joining in with a 74 year old Muslim grandad wasn’t something I’d ever expected to see.