Who would have thought that the band with a guitarist in a schoolboy’s uniform would be the one most profoundly affected by ageing? With their entire rhythm section now lost to death (Malcolm Young), retirement (Cliff Williams) and being a carer (Phil Rudd), AC/DC is now down to two core members. Angus Young still wears his blue velvet uniform, but beneath the cap, his hair is now pure white. Brian Johnson, having been out and then back in the band with his own health issues, simply appears delighted to be there.

Johnson is now 76, and there’s no point claiming his voice is what it once was. Even in 1980, on Back in Black, he sounded at the very top of his register (or, indeed, somewhere around the highest notes attainable by humans), and those songs cause him the most trouble tonight – he sometimes seems barely there, dropping octaves mid-line, struggling for power. No one minds: everyone in the stadium seems as happy as Johnson that he’s back in the band.

And what they are really here for is the riffs, anyway, which are still perfect: Back in Black, Highway to Hell, Whole Lotta Rosie, and 18 others. Young’s guitar tone is inimitable, and his effort unstinting: at 69 he still spends the whole show in perpetual motion. He’s helped by the current rhythm section – led by nephew Stevie Young – being the tightest set of replacements imaginable. Matt Laug, at last, is a drummer who seems content to play Phil Rudd’s parts without the need to add embellishment.

In truth, it’s more or less the same show AC/DC have been playing for decades, albeit the giant Rosie is now just on big screens rather than an inflatable. The emotional power comes from the suspicion that this world tour will surely be the band’s last, and from the palpable joy their thrilling, reductive, primal music has brought over so many years. It’s a long way to the top if you wanna rock’n’roll, they sang a very long time ago. They reached the top, and when they leave us, it will be from the top.