At a time when heavy metal is spiralling off into ever weirder sub-species - sports metal, necro-metal and whatever camp Satan-snoggers such as Marilyn Manson fall into, to name but three - Iron Maiden feel like the guitar-pounding counterparts of Disgusted of Tunbridge Wells.

The band was formed 25 years ago (how can gents of a certain age still possess such luxuriant manes?) and are among the last exponents of heavy rock as it was, before it became the domain of Prozac-munching teenage sociopaths.

Although the current album, Brave New World, flirts with such updated subject matter as father-son relationships ("Just for a second a glimpse of my father I see, and all the wounds are reopening again," screeches Bruce Dickinson on Blood Brothers, departing for once from the usual diet of Arthurian myth and legend), Iron Maiden will forever be a reassuring bulwark against the 21st century. When the designer Stella McCartney made Motorhead T-shirts briefly trendy last year, they probably did not see the irony.

The relatively tiny Shepherd's Bush Empire is off the beaten track for a group of their (still) arena-filling abilities, so this fan-club show was just about the hottest ticket in town, amazingly enough. The scaled-down staging meant that Eddie, Iron Maiden's faithful skeletal mascot, had to stay in his cave, but the compensation is that one drinks in the sight of Dickinson's roomy shorts at uncomfortably close range.

For his part, Dickinson looks oddly like Simon Le Bon of Duran Duran fame, but sings like a Nubian castrato, scaling the peaks of Wrath Child and Two Minutes to Midnight (played at 9.20pm, of course) with operatic hysteria.

Meanwhile, the drum-troglodyte Nicko McBrain chunders out a brutal backbeat that makes every number sound like Led Zeppelin's Immigrant Song. But there is no Jimmy Page to complement him on the guitar parts, which are undertaken by three characters straight from heavy metal central casting.

The Maiden's sound is too carbohydrate-rich to be entrusted to just one guitarist, so all three play in clangy unison, never using one note where a dozen will do. One of them has a penchant for wistful solo sojourns that transform the pained Blood Brothers into Bryan Adams-esque soft rock, making the girls in the house (very few, you will be surprised to learn) close their eyes and sway along.

But displays of virtuosity are pointless when the kids just wanna rock, and Iron Maiden will undoubtedly be doing their unreconstructed thing long into the new century.