John Harris: Mick and Keith? How about Fidel and Che, John and Paul, or Eric and Ernie?

Jagger delights his public by finding the exact mid-point between Bessie Smith and Graham Norton

But never mind all that. With Mick Jagger and Keith Richards freshly liberated from the condominiums and Home Counties farmsteads in which they spend their down time, the public can once again marvel at the threadbare state of their friendship. Last time out (in 2002, as I recall), Keith got off to a great start by wittily renaming Mick's most recent solo album Dogshit (as against Goddess) in the Doorway, and carpeting him for accepting a knighthood. In recent weeks he has surpassed even those slights, claiming that, contrary to rock myth, Mick has undersized genitals ("Ask Marianne Faithfull," he advised; no one has yet, though I dare say someone from Closersoon will). No sooner had he issued a mealy-mouthed apology than they were at it again: within seconds of his sighting of a Jagger-endorsed troupe of female dancers at a pre-show rehearsal, Keith put down his guitar and grunted, "No girls, or no show."

The penile accusation can, I suppose, be put down to playground japery, but the bust-up about the go-go girls is surely traceable to a point just short of the pair's DNA. Keith is a piratical rock'n'roller, suspicious of artifice and desperate to cling to the last shreds of the band's authenticity. Mick, by contrast, has long given the "A" word short shrift, preferring to embrace whatever musical currents are in vogue, graft burlesque distractions on to the band's performance and delight his public by finding the exact mid-point between Bessie Smith and Graham Norton. Within the Stones's chemistry, you thus find a familiar set of tensions: heart versus head, instinct against commerce, thundering recklessness versus careful finesse.

No matter that Jagger and Richards vent their differences via pantomimic nonsense; this is still the stuff of which all great male partnerships have been made: Lenin and Trotsky, Fidel and Che, John and Paul, Eric and Ernie, Tony and Gordon - all of them suit the model. The last two are a more perfect fit than most, as proved by their respective techniques at the conference podium. As the Labour Party's imminent arrival in Brighton will once again prove, Brown is a thrillingly intuitive performer, given to reminding the crowd of their roots and displaying a clumsy righteousness akin to the basic technique via which Keith makes his guitar go "clannnnng!". Blair, by contrast, has all the preening polish of an oratorical Jagger, which may not be a coincidence. Consider the recollection of one of his bandmates in the legendary student band Ugly Rumours: "He had a Mick Jaggeresque vocal delivery. Quite high, not enormous volume. But it was coupled with this very entertaining act. He definitely modelled himself on Jagger. There was a lot of 'Well, alright!'"

I bet there was. When you think about it, there still is. Indeed, extending the comparison might even shine light on how exactly the Prime Minister and Chancellor might proceed once the former has gone on his way. There will, it is safe to say, be no Westminster equivalent of the Stones's todger controversy. But wherever he chooses to go next, Mr Blair may very well attract notices akin to those that greeted such Jagger solo albums as She's the Boss (1985) and Primitive Cool (1987), rightly accused of being clinical, soulless and devoid of any Sturm und Drang. Brown, by contrast, may yet commence a prime ministership akin to Keith's 1988 Meisterwerk,Talk is Cheap, which returned his muse to rock'n'roll basics, reacquainted his audience with his feral spirit, and found the critics drooling.

Among Keith's hardcore fans, it remains fantastically popular. But guess what? Unfortunately, it didn't sell.