New technology brings new problems of violence and disorder. The scrap or school fight you used to deal with is now a media event, with an audience around the whole school and potentially - through sending digital images - across the local area and the whole country.
New mobile phones that take and send violent video clips are all the rage.
If you are a senior manager patrolling the corridors, then you may well have had to break up a happy slapping maelstrom.
Happy slapping involves a slap round the head. The novelty is that the perpetrator gets another pupil to video it. If the happy slap is a planned event, then a huge crowd is likely to be alerted and emerge all along the corridor.
This again is thanks to new technology - Bluetooth, an infra-red system that enables phone-users to send video nasties from one phone to others nearby, absolutely free of charge.
As the footage of the happy slap is beamed from one screen to another, the corridors fill up. As you wade your way through the crowd, a press pack of observers holds their phone cameras out and there's a frenzy of snapping.
The happy slapping phenomenon has been a craze for about three months.
Pupils say it's a new kind of real violence - a blend of reality TV and hand-held amateur video.
It doesn't stop there. Clips of girls fighting at a bus stop and a savage encounter between two boys brandishing weapons and covered in blood, all from nearby schools, have been shown to me.
"It tells other schools how hard your school is. It's proof! Then they try and send you something worse, go one better than you," is the way it's explained.
Other shots come from beyond school. On a night bus, a gang of youths announce "Happy slap take one!" - then one wallops a sleeping passenger in the face.
Clearly, some youngsters have always been fascinated with violent entertainment. But happy slap violence is sickeningly real and often selects random victims. It provides a new twist to X-rated PlayStation games and brutal gangsta rap songs that some teenagers live and breathe.
Our hope has to be that as new technology becomes old hat, we will return to more traditional forms of school friction, keeping it purely as a spectator sport for a local live audience and not for a global internet one.
The author is a senior manager at a large inner-city secondary school.
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