This may explain whyit is that now - when in rock 'n' roll terms they really are ageing - they can still come up with such a dynamic performance as they do at their Friends of the Earth benefit gig at the Clapham Grand. Unlike Jagger's struts, Anderson's movements are not imitations of youth. His trademark standing on one leg to play the flute, throwing and spinning the instrument with an expertise that suggests a spell in the majorettes, would be mad - and entertaining - coming from someone of any age. The music, its emphasis more on unexpectedly tough, bassy blues-rock than on the Tolkienesque symphonies of their middle period, is expert and exciting.
As this is a charity concert, they bring along some guests: Mick Abrahams, their former guitarist, Roy Harper, a bland old man of folk, and Gary Brooker of Procul Harum, who sings 'A Whiter Shade of Pale'. Less Live Aid than Still Alive Aid maybe, but Jethro Tull are in the prime of life.
The reason why Mark Eitzel's solo show at the Shaw Theatre is so packed is that he writes lyrics like: 'My old friend rigor mortis / He breathes in my face / Can you help me? / Nothing makes me laugh anymore.' And then there are the songs he writes when he's not in a good mood. His band, American Music Club, are admired for their sleepy, jangly sound, but only when combined with words so sharply observed, candid and - especially - miserable, Eitzel would have Morrissey telling him to cheer up.
An acoustic setfrom Eitzel should be a treat. Just the strum of minor chords and his sigh and moan of a voice, expressing confused, hurt vulnerability. And it is a treat, when he actually plays. Most of the evening, however, comprises Eitzel tuning up, apologising for how long it takes him to tune up, forgetting how the songs go, relating incomprehensible anecdotes, even stopping mid-song to point out his lyrical shortcomings: 'I could really take the piss out of this song - and so could you,' he laughs. Then he recites: 'When you left you took all memory of me with you,' before giving a quizzical, No-I-don't-know-what-it's-supposed-to-mean-either look.
This behaviour divides the audience into two camps. One applauds him for his rejection of an ultra-slick, over-rehearsed routine. The other is bored rigid. I started in the former camp, but by the 15th tuning-and- apologising routine, I was packing up my tent and preparing to move. 'I'm like that guy sitting on the couch at a party, playing his guitar all night, and you can't stop him singing,' Eitzel says. Honesty may be the best policy, but playing a decent show might worth trying, too.
Mark Eitzel with American Music Club: Reading Festival (071-284 2200) 28 Aug; Acropolis, Edinburgh (031-557 6969), 30 Aug.Reuse content