For one whose place in history is not so much secure as gloriously, unquestionably assured, Paul McCartney behaves as though there is some doubt. He is, lest we forget, not just any old ex-Beatle, but the Beatle. At least since John departed.

That insecurity is why he decided to rewrite history by bowdlerising Let It Be when he removed Phil Spector's production-rescue job, the one thing that made the album listenable. And it's surely why he engineered that silly hullaballoo about having some Beatles songs credited to McCartney/Lennon rather than Lennon/McCartney.

And, as if he were Gary Lightbody rather than Paul McCartney, he so desperately wants to be taken seriously. Hence the Fireman, the Liverpool Oratorio and that time he played celery with Super Furry Animals. Now, he's picked over the Beatles' carcass again and unearthed Carnival of Light, apparently an improvised 14-minute, vaguely avant-garde jam session recorded during the Penny Lane sessions. And he wants to release it. If he couldn't let Let It Be be - and in fairness, for all the pointless carnage he wrought, he'd always hated Spector's contribution - couldn't he at least show some decorum here?

If Carnival of Light sees the light of day, is it going to enhance the Beatles' standing? That's the very same Beatles who changed the world and whose influence and reputation remains undimmed. Of course it isn't. Is it going to make us think slightly less of them? In all probability, yes, and I'm inclined to trust the judgment of Ringo Starr, George Harrison and Yoko Ono, who vetoed its inclusion on Anthology and who (with Olivia Harrison standing in for George) will hopefully do their duty again this time. Carnival of Light may be the greatest 14 minutes in Beatledom and some people (ie me) are going to look pretty foolish if that's the case. Even so, I'd bet my sub-prime mortgage that it isn't and that phrase "14-minute jam session" strikes fear into the hearts of stouter men than myself. It's a soundcheck-esque rehearsal at best. At worst, it's Phish.

McCartney says it's the Beatles going "off-piste", or in other words, messing about. Frankly, I'd much rather hear them on-piste, crafting moments of genius such as Penny Lane. If Carnival of Light wasn't good enough to be released nearly 40 years ago (or on Anthology) then it's not now.

We've got the Beatles' body of work. It changed everything. Isn't that enough?