KOLO TOURE'S decision to wave goodbye to Arsenal and embrace the moneyed delights of Manchester City is significant, and not just for underlining the power of the petro-dollar. The defender's exit also means that not one of Arsene Wenger's 'Invincibles' still resides in north London: it is, officially, the end of an era.

On the face of it, this means little. The key players from Wenger's unbeatable class of 2003-04 - Thierry Henry, Patrick Vieira, Dennis Bergkamp, Freddie Ljungberg, Robert Pires, Ashley Cole et al - have long since departed and not all have been mourned by the red and white faithful.

Toure may not be missed, either. The Ivorian has not been at the peak of his powers for at least two years and spent most of last season casting sullen looks at William Gallas from the substitutes' bench. Besides, the £15m Arsenal are expected to receive is the most sugary of sweeteners, especially if some of it is used to fund a move for Fulham's impressive centre-half Brede Hangeland.

But, for the nostalgic minority, an Arsenal squad-sheet lacking any of the names from that exceptional band of title winners will feel sadly incomplete. Now, only Gael Clichy - a fringe player in 2003-04 - remains as a reminder of happier times.

Wenger cannot afford to indulge in such whimsy, of course. The Frenchman has never been one to indulge in reminiscing and much of his success at Arsenal has stemmed from his determination to focus on the future.

But losing Toure is a pointed reminder of Arsenal's remarkable plummet from dominant force to largely irrelevant also-rans in the space of five short years and Wenger, more than anyone, will be aware of the significance of seeing both Toure and Emmanuel Adebayor prised away by City - his most likely challengers for a place in the top four.

There are already rumblings of discontent around the Emirates at how Arsenal have developed a dangerous habit of losing players at the peak of their powers and a failure to recruit a worthwhile replacement would further sour the mood. Either way, the days when there was barely a chink of light in the Arsenal armoury could not seem further away on the cusp of this make-or-break season.