A thoroughly researched documentary blessed by control freaks who still can’t, or won’t, wrestle with the less flattering parts of the band’s history.

Despite having shut down legions of authors and filmmakers interested in their story, the members of Led Zeppelin said yes to Bernard MacMahon. Why?

They marked the moment when vast numbers of people, for the very first time, experienced rock ‘n’ roll as a kind of reckless orgy of the self.