It was certain to happen and now it has. The upstart M&C Saatchi has nosed ahead of its Saatchi & Saatchi mother ship in the latest AC Nielsen MMS billings league.
No matter that the now departed Sainsbury's TV account and Rover cars may have inflated M&C Saatchi's figures artificially.
No matter also that the figures take no account of the work produced by the Charlotte Street agency to run across Europe.
Nor is it much consolation that Saatchi & Saatchi's direct marketing, customer relationship marketing and PR activity are not reflected in the rankings or that the Saatchi & Saatchi name still eclipses that of M&C Saatchi globally.
None of this matters when egos and emotions are in play. Although only a third of Charlotte Street staffers were working at the agency when the Saatchi brothers went acrimoniously into exile, memories of that massive upheaval - when long friendships were sorely tested - are still fresh among some of the senior managers.
The unpalatable fact is that M&C Saatchi's UK billings are now higher than those of the agency its founding partners once ran. And, if the Champagne has been cracked open at Golden Square, the news will have provoked only icy smiles at Charlotte Street.
But if the latest rankings lead to a recognition that the two agencies share a common name but no longer a common culture, they will have performed a considerable service.
M&C Saatchi's collective character has always been relatively easy to define. It's the one the founding partners took with them five years ago.
It's brash and flash with a touch of arrogance and has proved how effective it can be when not distracted by hubris or share price.
Saatchi & Saatchi is much harder to get a handle on. It still glories in the 'nothing is impossible' legacy the brothers bequeathed it, yet its ethos is more about pragmatism, being down to earth and hard working.
Nothing wrong with that, particularly as the Saatchis network is looking much better organised these days. And although the vision expounded by Kevin Roberts, the chief executive, of Saatchis as a 'global creative boutique' seems curiously contradictory, he does at least have a vision.
Under the wing of the hugely ambitious Maurice Levy, the Publicis president, its future looks brighter than for some time. If only it can finally bury its past.