Yet some songs continue to resist that separation. Tony Hadley will bring the unmistakable voice behind songs including Gold, True and Through the Barricades. JLS, meanwhile, represent a later chapter in British pop with five UK number-one singles and songs including Beat Again, Everybody in Love and The Club Is Alive. That helps explain why festivals with line-ups spanning several generations can create a particular kind of atmosphere. But nostalgia alone does not explain why these songs continue to work.