The idea that if no one carried a weapon, we'd all be safer, is no doubt true, but it's never going to be the case. Disarming the general public is not going to stop criminals doing so, indeed it cements the advantage of the criminal over the law-abiding. Additionally, the police seem to be better armed than ever. Why not set an example, and disarm the coppers? Stupid idea, huh? But if the police are citizens like the rest of us, rather than paramilitary agents of the state, then they should have no more right than the rest of us to weaponry.
We all have a right to self-defence. This is dictated by natural law firstly, and is a valid legal defence against charges of violent conduct. However, the statute law does everything it can to ensure that an ordinary citizen cannot exercise this right. Under the present rules, you have a right to be a victim, and nothing more. Other, non-lethal weapons, such as pepper sprays or tazers, which one can see dangling from the belts of today's coppers, are also banned.
Now, I recognise that most people do not support our right to bear arms. After decades of propaganda, they seem to equate a legal right to own a weapon with a legal right to kill anyone they don't like, which is of course nonsense. They do not want liberty, they want security, to hide behind the skirts of the ever-more heavily-armed police, notwithstanding the face that its highly unlikely that the police will be around at the moment they're needed.
The reasons for the current upsurge in knife crimes are no doubt complex. The social engineers' assault on the family and the consequent fragmentation of society may explain it in part, massive exposure to violent television and video games may also be relevant. It may also be a blow-back from the feminisation of boys by the state school system, which gives them no outlet for, and hence no ability to control, their natural violent instincts.
Allowing the population to tool up may not provide a short-term solution, but neither will ramping up the police state.