With ageing rivals from Black Sabbath to AC/DC having finally succumbed to metal fatigue, there are no obvious signs of rust on Iron Maiden. Granted, they are more venerable old men than new wave of British heavy metal, but they are still one of the world’s most popular bands, with a tour schedule that would give much younger men hernias. This latest trek visits more than 100 cities, and singer Bruce Dickinson is even flying the band between them on their own plane, Ed Force One. At 58, he’s not quite ready for a bus pass, but a brush with cancer seems to have underlined his mortality and rejuvenated the frontman and the band, who perform as if they realise they have some of the best jobs in the world but they won’t last forever.
Thus, musicians past 60 cling to the remnants of very metal hair and play instruments behind their backs or while dancing on one leg. Dickinson embraces the dark arts of maximum metal silliness. He gazes into a steaming cauldron, leaps off the drum riser, dons a monkey head mask, battles a giant Ed (the band’s death’s head mascot) and introduces a “song from the mists of time” with the “here’s one we made earlier” catchphrase from Blue Peter. The singer cheekily calculates that anyone in the audience born in 1983 could be the result of their parents having “mum and dad sex” listening to 1982 smoochie, Children of the Damned.

Although Dickinson reveals that reaching the high notes requires some “nut squeezing” nowadays, the only other concession to ageing is that most songs from 2015’s globally chart-steamrollering The Book of Souls don’t rock as fast as hurtling oldies Wrathchild, The Trooper or the ridiculously demonic The Number of the Beast. Some songs are so long that it takes the band two hours to play 14. And yet, there’s something touching in Maiden’s relentless rocking and the way bassist Steve Harris and the band’s three guitarists grin at each other while perfecting their “machine gun” poses for the millionth time.
The none-more-rugged singer makes a speech about the “blithering idiots, now running the world, with their fingers on the nuclear button”, and when he points to flags showing where fans have come from, there are people from as far afield as Japan and Argentina. “We don’t care where you come from or what you do in your spare time. If you come to an Iron Maiden show, you’re family.” Who would have thought that in such crazy times a grizzly old rock band in bullet belts singing about demons, warfare, apocalypse and mass murder would emerge as a beacon of unity, peace, love and understanding? God (or the other fella) bless them.
• At Barclaycard arena, Birmingham, 21 May. Then touring.