Keith Duggan Sideline Cut

The problem for Roy Keane is not the ferocity of his words but that he is unable to back them up on England's football fields. All great sporting dynasties have their dressingroom agitators. And although Eric Cantona was Manchester United's enigmatic leader during the nascent years of the Premiership, he famously walked away to answer the call of art, drama and beach football.

Since the Frenchman's admirably complete disappearance from English soccer culture, Keane has not so much grown into the role of United's leader as utterly consumed it, to the point of becoming a figure of caricature. All through this week, the revelations have come hot and heavy portraying Keane as a raging phantasm in the plush corridors of Old Trafford, terrorising the millionaire set with that gimlet eye, the razor-thin smile and that Corkonian quaver in his voice, much like Jack Nicholson in The Shining.

That Alex Ferguson elected to bury Keane's public interview haranguing all, some or none of his team-mates, depending on which version of events are to be believed, presents the intriguing possibility of football's most famous house on the brink of mutiny. It adds a genuine edge to Chelsea's visit to Old Trafford tomorrow, a game whose meaning, atmosphere and potential hostility would make it a perfect hunting ground for the vintage Keane.

There was a remoteness and acceptance about Ferguson's voice in the interviews that were broadcast following Wednesday night's pale defeat to Lille, a match that illuminated the uncertainty which stalks United these days. Ferguson's contention that the night had been a learning experience for the team's younger players sounded like a plea for clemency. Lille are precisely the kind of competitive but average European team United habitually used to swat aside half a decade ago.

Before that game, Ferguson asserted that, as a club, United always espoused the virtues of European football, moderating the claim that the club had enjoyed some wonderful nights in the prestigious competition by acknowledging United had only won it twice. As George Best, the black and white genius of United's emblematic 1968 victory lies in a London hospital ravaged by illness and a misspent life, so the memory of Ferguson's great modern triumph is also dimming.

While United's 1999 Champions League win against Bayern Munich was undeniably thrilling, revisionists could argue the smash-and-grab goals, both from corners, in the last two minutes of the final - Best had famously abandoned hope and had just left the arena - were touched with fortune. Still, the United of that era played the game with fearlessness and arrogance and the fact was that after conceding the equaliser Bayern froze in expectant terror at what was to come. Such was the power United generated then. But if the lateness of their comeback against Bayern leaves that campaign open to the suggestion of luck, their obliteration of Juventus in the semi-final, mercilessly driven onwards by a thundering Keane, confirmed their status as worthy winners.

England, Europe and the world seemed like a red carpet for United at that point. In retrospect, the fanciful association with the New York Yankees, the glamorous if vacuous mid-season tournament in Brazil, and the alleged rows between Ferguson and Posh Spice over David Beckham's shopping duties all seem like glaring signs of an entity spinning away from its axis.

United were Premiership champions as recently as 2002/03 but the emergence of Chelsea has eviscerated the sense of security United felt about the domestic competition. The FA Cup, which United demoted to a charming but unimportant relic of the old days during their days of pomp, provided them with their sole potential for joy last season. And they were unlucky not to win the final, even if there was a poignancy about Arsenal and United, the rivalry on which the Premiership was founded, suffering the slow death of a penalty shoot-out for a prize that no longer glitters as it once did.

The metamorphosis of United into a public, trading company, the shadowy spectre of the Glazer family and the steady diminishment in talent of United's playing roster - combined with the towering wage bill - have distorted the way Old Trafford's fan base views the club.

A generation of supporters, in Manchester and the thousands that regularly visit from this country and others, were lulled into a sense of lazy complacency by years of easy success in a lopsided league. Keane sensed that muted smugness and registered his unease at Old Trafford's increasingly corporate and dead atmosphere with his memorable swipe at the prawn-sandwich brigade. As often with Keane though, the truth and point of the message was obscured by its stinging wit.

Now, in what may be the final autumn of the Ferguson/Keane alliance, the Irishman is injured, frustrated and airing his thoughts in his usual succinct and lacerating style.

Revelations that Keane once exploded at the sight of Ruud van Nistelrooy combing his locks before a television interview are genuinely humorous to imagine. Lord knows how Keano used to cope with the Beckster's mirror time and one cannot imagine himself offering to help braid Rio Ferdinand's hair in the hours before tomorrow's game.

The point is Keane is doing this week what he has always done. We have all seen close-up images of the Irishman shredding colleagues for casual play or lazy defending in words which, though unheard, are clearly not pretty. Every group has its leader, its mouth. When John Lennon was asked if Ringo Starr was the best drummer in the world, he deadpanned: "He's not even the best drummer in the Beatles." As a line, it was pricelessly funny but from the percussionist's perspective, it was cruel and it reinforced who was who in the group.

Keane has earned the right to criticise and explode through over a decade of consistently brilliant and tough midfield play and because, long ago, Ferguson gave him the imprimatur to do so. Injured, and as frustrated as his manager by the displays given by United for the past two months, Keane has had to watch from the sidelines as teams that once cowered before the Red Devils now treat them like any other team.

And he has been unsparing in his criticism, as always. The difference is that his views were spoken in an air-conditioned television studio and not in the midst of a Saturday match, with 40,000 baying fans drowning out the severe truth of this views.

The bones of his message are undeniably correct. If the players and management at Manchester United are truly entertaining the idea they are a great club, then their current predicament is unacceptable.

That van Nistelrooy has supported Keane's stance this week is significant. And ultimately the Irishman will be putting his money where his mouth is. When he returns to the first team, the pressure will be on him to lead with the authority and defiance of old. There is reason to suspect that with Keane back in harness and the return to health of other old hands that United have enough skill and stealth to make something from this season, even a devil-may-care run in the Champions League. But tomorrow, Keane will languish in the stands.

The 90 minutes against Chelsea will reveal much about the weight of the captain's words, now so fearfully guarded by Alex Ferguson.