It is often said that heavy metal and pop have much more in common than either would like to admit, and there isn't a band for whom the blurring of the lines is more evident than Iron Maiden. They have always played their shows like heavier versions of the Moulin Rouge: heroically ridiculous, such gigs are as much a spectacle as anything offered by Lady GaGa.
Lest we offend too many metalheads, Iron Maiden's music, hooky and lustful as it is, is poundingly heavy and far more grandiose than pop. Things here begin with duller material from the group's last album, Final Frontier, which we are asked to wade through before being allowed a classic. Thus they eventually bestow a vigorous "Two Minutes To Midnight", sending a wild crowd into its first devil-horned paroxysms.
The first half of the show follows this pattern – our next big one is "Dance of Death". Bruce Dickinson is crouched down, writhing his arms, bathed in a red spotlight like a necromancer in combat trousers. Behind him, the band skip around like a camp horde, guitars thrust up and out from the groin. In case anyone misses the message, there is a big picture of a magic skeleton behind them.
Immediately after that, there is a boom and the band blast into "The Trooper". It is an absolute assault, four guitars on the lip of the stage aimed like Gatling guns. Dickinson materialises upstage, wearing a red Victorian infantry jacket, waving a Union Jack as if he has held Rourke's Drift single-handed. It is endearingly OTT and we are cooking with gas as they bring out the big guns: "The Wicker Man", "Blood Brothers" and "Number of the Beast".
We're joined by a 12ft version of the band's mascot, Eddie, for the end of "The Evil That Men Do". He saunters around playing a guitar – of course – but before we can process that we are into "Fear of the Dark", a series of epic solos loosely connected by a chorus, which is played like the future of the Earth depends on upon it.
One caveat: the sound quality is dreadful, thanks to the acoustic awfulness of the O2, and we lose most of the subtlety – some very familiar songs are rather hard to recognise. Still, it is a blinding show, a brilliant fusion of high camp and proper heaviness. Two days later, I remain deaf.