The problem with knives is the misplaced notion of 'respect' that young lads think they achieve by carrying a weapon.
Of course, in heated arguments, knives get waved around, and that's a very short step to adrenaline-fuelled rage taking over, and knives get used, often fatally.
The way to stop it is to educate young people that respect is earned by personal attitudes, not fear of violence.
But of course, it's not sexy enough for the government to put time and money into it, apart from the usual bleating about 'our children ...' which does nothing to actually address the problem.