As a career-spanning documentary hits cinemas and the band eye two nights at Knebworth, they revisit their path from pubs to stadiums – but how did they get through their crisis-filled 1990s?

When I ask Iron Maiden bassist and founder Steve Harris about the fact his band have lasted for more than half a century, he sounds bewildered, as if he’s put something down then forgotten where he’s left it. “It’s gone so quick. You go on tour for a few months and it seems to fly, but so much happens. Our whole career is an extension of that – for 50 years.”

He’s looking back on how he steered one of the most influential – and deeply idiosyncratic – British bands in history. Catapulted to the premier league of 80s metal on the back of galloping, theatrical, multi-platinum LPs including The Number of the Beast, Powerslave and Seventh Son of a Seventh Son, Iron Maiden not only survived the mid-90s slump that befell many metal bands, but got even more heavy and ambitious.