“You start at the end. You start with emptiness. You start with nothing. You start with the void.”

So writes Bono in his unusually revealing liner notes for U2’s long-awaited and seriously overdue fourteenth studio album, Songs of Experience. But we can’t start at the end here because the band’s journey still seems so very far from over. Nor can we start at the beginning, because that was more than 40 years ago in a progressive Dublin secondary school – and oh so much has happened since the then 15-year-old Laurence Joseph Mullen Jr. pinned a notice to the Mount Temple message board looking to form a band.

U2’s lengthy rock ‘n’ roll career has happened in quite distinct phases, and notwithstanding their forthcoming Experience + Innocence tour in 2018, the release of Songs of Experience is the definitive bookend of a particularly turbulent period. So let’s leapfrog the emptiness, the nothing and the void, and start proceedings where this particular phase began: in a stationary private Learjet parked on a quiet runway in Cologne Bonn Airport on a bitterly cold night in early October 2013.