Music: The dinosaursthat beat Darwin

Heavy metal is still hard. It's England that's gone soft. Just ask Iron Maiden.

It's 11.50pm and, slightly ahead of themselves, Iron Maiden have just launched into "Two Minutes to Midnight". At a packed open-air fairground in Dos Hermanas, Seville, the Spanish leg of the band's nine-month world tour is drawing to a close. The phantasmagoria on stage is the only source of light, revealing a fairly even mix of senoras and senoritas aged 17- 30. Seems that here, in the heart of Andalucia, heavy metal's image as a rite of passage enjoyed almost exclusively by adolescent males doesn't quite fit.

In a week's time, Iron Maiden will be touring Britain, where the demographics will be more predictable and the cities less picturesque. Steve Harris, the band's 42-year-old bass-player, founding member and songwriter, admits that Maiden currently have less cachet at home. "The British press have been chipping away at us for about 10 years", he confides. "I'd like to tell you that it doesn't have an effect, but it does."

Formed in London's East End against the grain of the nascent punk scene of 1976, Iron Maiden have had 12 top 20 albums and 20 top 20 singles in the UK. Worldwide, they've sold over 50 million records, and at their commercial peak circa 1983-85, they could sell out California's 13,000 capacity Long Beach Arena for four nights running.

Pleasingly, all five of the current line-up are working-class boys made (very) good. As Mick Wall's affectionate biography Run To The Hills testifies, there was a time when the respective fathers of guitarist Dave Murray and drummer Nicko McBrain used to share a quiet drink with Ronnie and Reggie Kray. Now, McBrain has a nice gaff in Florida, while Murray lives on the exotic island of Maui with his Californian-born wife, Tamar.

Even at an epic 10 minutes long, the band's last single "The Angel & The Gambler" confounded radio schedulers by charting at number 18. Some might poke fun at the band's anachronistic image and comic-book lyrics, but beyond the letters pages of Mix-Mag and The Face, Iron Maiden's loyal constituency is clearly still out there.

And what this band understands very well, it seems, is that giving your constituency exactly what it wants is half the battle. To this end, they've just re-released their first 12 studio albums as enhanced CD-Roms, each featuring bonus videos, biographies and a selection of artwork depicting the various incarnations of their ghoulish mascot Eddie Ed. For your average, IT-equipped Maidenite, it's an irresistible (if expensive) package.

Inadvertently, such clever marketing only serves to highlight the increasingly marginalised status of heavy metal in Britain. The on-going decline in the genre's album sales here is undeniable, and Maiden, though still fairing much better than most, have not emerged unscathed. The X-Factor reached a respectable enough number eight in 1995, but it was the band's first album in 14 years not to go top five. In March of this year, Virtual XI peaked at number sixteen. Safe in the knowledge that Maiden are still shifting mega-units in other territories, Harris doesn't seem perturbed. "Look what's happened with Aerosmith," he says, pushing back a mop of near waist-length hair. "Not so long ago they couldn't get arrested, and now they've just had another American number one. These things go in cycles."

While trying to explain metal's current decline in popularity here is a bit like trying to account for the demise of the dinosaurs (and there are those, of course, who would argue that that's a particularly apt simile), changes in the make-up of the UK's popular music press in recent years seem germane. When Iron Maiden first signed to EMI records in 1979, they were at the forefront of what became known as "The New Wave Of British Heavy Metal". This somewhat tongue-in-cheek term was coined by then Sounds journalist Geoff Barton. As a scene built around predominately Northern, working class bands, such as The Tygers Of Pan Tang and Def Leppard, caught the imagination of a certain section of the record-buying public, Barton and his editor at Sounds, Alan Lewis, spotted a gap in the market. In a world before Q, Mojo and Select, their seminal hard-rock magazine, Kerrang!, had plenty of elbow room on the newsagent's shelves.

Some 18 years on, that hard "K" in Kerrang! is sounding slightly softer. This week's issue might have Black Sabbath on the cover, but inside there's a feature on hip-hop posse Cypress Hill, and live coverage of indie acts such as Placebo and Carrie. In the magazine's Eighties' heyday, this would have been tantamount to heresy.

"The explanation's simple, really", explains Phil Alexander, the current editor. "Nirvana and the whole Seattle scene helped broaden peoples attitudes, and in the last five years or so, rock music has really evolved. To our way of thinking, a band like Placebo are worthy of coverage simply because of their status as a rock act."

Thus, while Kerrang's current modus operandi makes perfect sense, traditional hard rock acts like Iron Maiden are finding it harder to garner column- inches.

Beyond these shores, where the print media are not such powerful arbiters of taste, Iron Maiden are huge. Harris tells me that the European leg of the world tour included two sold out gigs in Istanbul. "We knew from the response on our web-page that we had fans there, but we didn't expect them to know the lyrics to every song," he says.

In Brazil, where the massive success of indigenous acts such as thrash- metal exponents Sepultura testifies to hard-rock's enduring appeal, it's a similar story. When guitarists Dave Murray and Janick Gers visited the football club Santos, on a recent promotional visit, they were amazed to discover that the not-quite-legendary defensive midfielder Ronaldao - he of Brazil's 1994 World Cup Squad - was a Maiden fan. "Santos listen to our stuff before they go on the pitch," says Murray. "Apparently it gets the old adrenaline going," adds Gers.

Back at Dos Hermanos in Seville, Eddie Ed is making his customary appearance. As the riff from the band's eponymous anthem fires up, inflatable representations of his werewolf-like hands swell to book-end the stage, while his horrible head completes a comic-horror tableau.

"MTV don't play much Iron Maiden at the moment, but we know that the people with the very best taste in music are here tonight," booms Blaze Bayley, Maiden's vocalist.

Post-gig, as I watched the band embark on yet another round of memorabilia- signing with good humour and endless patience, my heart gave a little kerrang. Long may they rock.

Iron Maiden are on tour in the UK from 17 November