Iron Maiden, Metro Radio Arena, Newcastle<br/>Tenacious D, Hammersmith Apollo, London

Mock rock versus the real deal. That was the compare and contrast concept for this week's column. But reality has a way of throwing a spanner in the works.

On their latest arena tour, Iron Maiden fans are being charged £37 for the privilege of hearing the band's brand new album - which many of them haven't yet bought, or listened to much - played in its entirety (with a handful of oldies thrown in at the end). That is to say, the privilege of being advertised to.

A Matter of Life and Death is something of a concept album concerning warfare, religion, and the causal connections between the two. Accordingly, Maiden enter the stage to the sound of war-movie music, in front of a backdrop which initially shows the bombed-out ruins of what might be Strasbourg 1944 or, given the band's East End origins, Stratford, then progressively depicts Eddie - the band's zombie/scarecrow mascot - in a variety of martial scenarios (Eddie dressed as a Second World War Tommy, Eddie marching in front of a Chieftain tank, and so on).

Such gaucheness is only to be expected from a band whose passports all say 50 or nearly, but whose mental age is still 12. With verses like "Far away from the land of our birth/ We fly a flag in some foreign earth/ We sailed away like our fathers before/ These colours don't run, from a cold bloody war", AMOLAD is clearly an album with its heart in the right place, but it is also clearly the work of overgrown children (all that histrionic imagery: "valkyries" this, "Armageddon" that...)

As they riff away, in front of a wall of painted sandbags, it occurs that this is a band who are, both literally and metaphorically, entrenched. With Adrian Smith, Janick Gers and Dave Murray twiddling away and Bruce Dickinson shrieking at that unmistakeable scalded-cat pitch, this is an album - and a performance - which could have come from any year since 1981 (the year Dickinson joined).

Tonight, the audience too is a very 1981 crowd, and also one of the ugliest I've seen. Everybody's dressed in washed-out, off-black denim, as though faded by a quarter-century of getting your mum to do your laundry.

The appeal of Maiden to children is no mystery. IM aren't only pre-political. Almost uniquely among heavy metal bands, they're pre-sexual too. They're stuck in the pre-pubescent phase of playing with toy soldiers, and reading Battle and Warlord.

None of which would matter if, on the night, Maiden gave good show. But they don't. Bruce Dickinson, inseparable in my mind from Bill Oddie (same stature, speaking voice, and puckish demeanour) leaps from podium to podium, but rarely speaks, aside from raising some cheap laughs by describing reality TV as "bollocks". The theory, he explains, is that the new album should be allowed to speak for itself..

Oh, it speaks. For what seems like an eternity (10 songs in 70 minutes). But by the time they reward our patience with a handful of oldies ("Two Minutes", "Fear of The Dark", "The Evil That Men Do", "Hallowed Be Thy Name"), the disappointed faces around me have already stopped listening.

What hell hath Jack Black's scene-stealing turn in High Fidelity unleashed? By mesmerising the gullible into the temporary delusion that he is actually funny (a delusion which is curable in most cases by watching School of Rock, catching the trailer to The Pick Of Destiny, or merely glancing at a poster for Nacho Libre), Black has gurned and mugged himself into a position where his comedy-rock band, Tenacious D, can fill major venues.

A gonzo duo in the Bill and Ted/Beavis and Butthead/Wayne and Garth tradition (with just a hint of Jake and Elwood), Tenacious D allows 37-year-old Black and his 46-year-old sidekick (and classically-trained guitarist) Kyle Gass indulge in puerile fratboy humour.

But, on their own terms, Jables and Kage (to give them their stage names) entertain. You go to a Tenacious D concert, and you'll get dancing robots, skits involving the Devil and Jesus challenging them to a "rock-off" (hey, I never said it was hilarious), band members dressed as Col Sanders and Charlie Chaplin, classic rock covers (including a Tommy medley), and their own songs such as the lurve-ballad spoof "Fuck Her Gently", "Tribute" (which crosses The Charlie Daniels Band's "The Devil Went Down To Georgia" with Led Zeppelin's "Stairway To Heaven"), and "The Pick Of Destiny", which boasts a hook that stays in the brain longer than anything on the latest Maiden album.

In purely relative terms, the jokers edge out the real rockers. In either case, I can think of better things to do with my 37 quid...

s.price@independent.co.uk