The road to Glastonbury: What makes a Pyramid Stage headliner, and why is it so hard to find them?
As Worthy Farm gears up once again to welcome Glastonbury fans this week, the question of who should take top billing at the UK’s best-loved music festival is becoming harder to answer. Not to mention increasingly controversial. So what do organisers look for in a headline act? And should they be changing tack? Roisin O’Connor reports