Sideline Cut:Anyone who feared a gulf had developed between big-time sports stars and their fans probably thought differently after the much-publicised connection between Trevor Brennan, the Toulouse rugby folk hero, and the Ulster rugby supporter who truly got bang for his buck at last Sunday's match.

The photograph that captured Brennan's haymaker connecting with the Ulster fan confirmed the stars are not so untouchable they will no longer mingle with the fans.

It is clear Trevor Brennan was animated and annoyed about something. Whether the Ulster fan was the legitimate target of his annoyance is another matter.

The expression on the fan's face is not so much fear or pain as thoughtful surprise, as if he were saying, "Well, I certainly never expected this."

The rights and wrongs of the Toulouse incident will undoubtedly be thrashed out over the coming weeks. Rugby being what it is, there were probably several to hundreds of vastly experienced solicitors within a stone's throw, or indeed a wild punch, of the incident who will be happy to advise the unfortunate Ulster fan what the holy books of law have to say about the incident.

And even though the episode occurred on French soil, it was quickly reinterpreted as a good old Irish barney between the embittered Paddies and their sighing cousins in the North. The Toulouse angle, that Brennan had been incited by sectarian abuse or his mother had been gravely insulted, was reported widely in the Irish newspapers.

The switchboard at Montrose was lit all morning with men and women patiently waiting to vouch for Trevor Brennan's innate goodness as a human being.

The most surprising of these character witnesses was the RTÉ frontman Hector Ó hEochagáin. The excitable Navan man had filmed with the Toulouse flanker for his television series on the beautiful and the famous, and he was adamant, in his characteristic Midlands drawl, that "Threv-awh" was sound as a pound.

It has been alleged that in his younger days Trevor was known to have something of a short fuse, an Achilles heel he overcame in his vintage years with Toulouse. But if any shred of that hot temper remained, surely a week in the company of the zany, nerve-wracking Hector - probably the most giddy television creation since Graham Norton moonlighted as Fr Noel Furlong, the dancing priest in Father Ted - would have tested the patience of the rugby man to the limit.

As Hector mounted a passionate defence of his former subject, the Ulster rugby spokesman listened patiently on the other line, soothing the Meath entertainer with a flattering "And by the way, Hector, mate, I love yer work", before calmly outlining why this was another attempt to tar all of Ulster with the brush of sectarianism and the rest of it. For Uncle Joe Duffy, it made for a delicate hour of diplomatic peace-brokering.

But as the unfortunate incident spins on toward whatever conclusion, it is probably worth considering the strange and sometimes precarious business of being a fan.

Because the fan - and we all know this is true - must believe that he or she can, in some way, affect or even dictate the outcome of any given sporting occasion. If there is any truth to the theory that all people are, to some degree, a bit mad in the head, then surely the general behaviour at sporting fixtures offers substance.

Normally mild and responsible adults can forget themselves as soon as the whistle blows. They can indulge their tics and mannerisms and gnash their teeth, rock back and over, scratch compulsively or speak in tongues and nobody pays a blind bit of notice. All bets are off once a fan takes his place on the terrace or in the stand.

Occasionally, at rugby or GAA games, for instance, former players, even "greats", will stand or sit among the regular fans. And they almost always behave impeccably, coolly watching the proceedings, often in complete silence, and exiting with wistful smiles on their faces whether in triumph or defeat. Inside, they are probably dealing with the heartbreaking knowledge that they cannot play at the top any anymore, a cruelty that revisits them every time they go to see a match.

But, as they stand surrounded by all manner of lunatics, they are probably also quietly relieved they simply managed to survive all those years wearing their team's colours.

For regular fans, who never played at the top and have not even a remote clue what it is like "out there", will behave as if they set the standard. They will gasp in disbelieving horror at every mistake and turn away in disgust at the efforts of a player they deem unworthy. And often, they will encourage or lustily demand the players on their team bust, deck, creel and hammer the boys on the other team.

"Hit him, for f*** sake," the fan to your left will scream repeatedly in exasperation. The implication is, of course, that if he were out there on the field, he would be swatting the opposition like flies. It does not matter that he is a squishy sort of buck, about as chiselled and buff as a loaf of freshly baked bread. He is a fan and he can pretend to be whatever and whomever he likes.

Many fans talk a lot. Sometimes they talk to themselves, sometimes to God or long-deceased relatives or even to the person sitting alongside. Often the conversations go something like: "Yes. Yes. YES. NOW. NOW. Give it. Brilliant. Watch that - YES. THERE HE IS. LET IT GO! LET IT GO! AHHHHHHHH! YA GOBSHITE!"

And fans talk to their players. We have all heard it. They say curious things.

Many years ago, an Ulster championship match was coloured by a fan who yelled at the opposing star midfielder, every time he got the ball, "You are nothing but a rent boy."

At a Connacht game, another glittering player was earnestly advised by a visiting fan, "Get your home life in order."

Years ago, at a particularly appalling basketball match that attracted few fans, one of their number stood up and spoke for the rest when he shouted in despair, "To think I gave up Blind Date to come and watch this."

Fans are weird and they say weird things. It could well have been that Trevor Brennan's public house was insulted during those contentious minutes last Sunday.

When matters spiral out of control in sport, the tendency is for everyone to take a sober step back and announce such behaviour would never be tolerated by the law if it happened on the street. Unfortunately, the general behaviour at sports events bears absolutely no relation to what happens on the street.

Look around you. People go strange. Some turn white and silent. Others go purple and start foaming like the kid in The Exorcist. Fathers bring boys or girls to matches and proceed to shame and psychologically scar them by threatening priests, rowing with ice-cream vendors, weeping hysterically and sometimes, unforgivably. They even sing.

Fans shout and yell and forget themselves. Fans think they are invisible, particularly to the players. Yet in other ways, we fans delude ourselves that we can understand and know what the players are going through. Fans comfort themselves with the dream that in the matter of the game, they are somehow equal to the players. They don't, however, really expect the players to engage with them in that fantasy. They don't expect the players to come crashing into the bliss of their turf, those crowded houses in the stands and terraces where they feel safe and far away from the real world. Which is why so many fans looked as if they couldn't believe their eyes when big Trevor Brennan decided to pay a visit last week.

As Frederick Exley asked in A Fan's Notes all those years ago, "What good are dreams if they come true?"