Guinness is running an advertisement on TV at the moment whereby football fans in a pub are watching a match and sharing a moment of collective grief when suddenly, a supporter of the opposing team mistakenly rushes through the door in triumph. Realising his error, he makes a rapid withdrawal. Cue wry smiles on and off the screen.

Although only two fractions of the game are shown during the advert there is no mistaking the sport involved. The scene is unthinkable in any sport other than soccer.

Why would the opposing fan leave the pub in such a hurry? Because he was afraid of the slagging?

Now the advertisement is sort of amusing in a black humour sort of way. But it’s also sort of sinister.

A chap from Belfast I used to work with told me that he was once arrested by the army when he was younger. They bundled him into the back of the ‘pig’ and brought him to the top of the Shankill Road. Then they threw him out, shouted ‘Fenian’ and drove off laughing. He hot-footed it out of the area without harm coming to him. I suppose it was an amusing thing to do.

Somehow everyone can understand that sectarianism makes this last story far worse than the TV advert. Everyone can understand how lethal this primitive tribalism has been in Ireland.

What people can’t seem to concede is that this visceral loathing for the ‘other’ is what is so appealing to many soccer supporters. That is, to a large percentage of fans who actually attend soccer matches. The proportion of these fans to the general soccer supporter would be similar to the numbers who have disgraced the name of England around the world to the actual population of England. In other words – a very small number.

Not only does soccer attract this small minority but also it allows them to influence the whole. This tribalism and aggression spreads to a large number of otherwise normal people who seem to lose the run of themselves when confronted with men kicking a lump of leather around a field.

I have witnessed this phenomenon many times in my trails around London as an Arsenal supporter. The first match I went to was Arsenal against Chelsea at Stamford Bridge.

Getting out of the tube at Fulham Broadway was one of the biggest culture shocks of my life. There were hundreds of riot police on foot and on horseback. It was like a scene from a war movie. Even for a lad used to crossing the border into Fermanagh, this was militarisation in a big way.

Inside the ground (we had to go to the Chelsea end) was just 90 minutes of aggression and hostility. It was shocking.

But you got used to it. A couple of years later I brought my wife to see Arsenal against Newcastle at Highbury. She couldn’t believe the aggression. I sat with a silly grin on my face. You have to admit it’s sort of funny to see people behave in this way.

I remember after a match at West Ham, we (the Arsenal fans) were locked into the ground for a half hour after the game for security reasons. Then the riot police marched us to the tube station. At one point some young chaps crossed the road against the orders of the police. The police then lined up like cavalry across the road and ran the horses at us to show who was boss. You actually have to experience the effect – you can’t imagine the terror as people clambered against walls to get away from the horses.

Ultimately, in this general environment, violence is the product and scenes like we witnessed in Cardiff two weeks ago ensue. Can anyone doubt that if the Cardiff fans were allowed access to the Leeds fans that there wouldn’t be a fatality? It is utter madness.

I believe that the major cause of this is the long-term practice of segregation.

Contrary to its short-term purpose – to protect fans – segregation is actually reinforcing the culture of tribalism and aggression in soccer. No one need behave decently at a soccer match, it’s just not expected.

In this atmosphere, the worst elements of society are attracted to soccer grounds. They feed off the sectarianism and then practice their violence away from grounds. The police then bring in more measures, intelligence gathering and preventive detention and so on, to curb the violence and the downward cycle continues.

What must happen is for soccer bosses to leave all this behind and start planning for integration of fans immediately. For some this is unthinkable.

Imagine Man United and Liverpool fans sitting side by side at a match. Is it really too much to expect people to behave with dignity? The fact is that the vast majority would. They would temper their comments. Peer pressure that exists in all other walks of life would force a change. It already has in the case of racism at soccer matches.

The process should start right away. Integrate parts of stadia. Integrate matches without a history of friction. Make it clear that better standards of behaviour are expected and that aggression will not be tolerated and facilitated. Lock up people who behave like animals (unlike the ridiculous leniency shown after the Lansdowne Road riot). Leave that entire culture behind.

It’s a tall order. But for both soccer and wider society there is no alternative.