Why even use a knife? Why not use a screwdriver with a sharpened point? https://en.wikipedia.org/wiki/Stiletto This kind of weapon was even preferred as a trusting weapons during days, when civilized people still killed each other with bladed weapons. Knights used those. And screwdrivers are able to withstand much more force than some kitchen-knife. They wouldn't break, even if they'd hit some bone with full force, and would be able to even penetrate the skull. If authorities want to harass innocent people for carrying knifes, why not stab people with screwdrivers? That even saves money for fines, which would otherwise used to pay for this harassment. edit: I see the actions of the UK in such a manner, that it wants its citizens to think about how they can best kill each other. At least, that's what happens when I read about such laws. I always think about how to find something cheaper and more effective than what has been outlawed, while technically obeying every letter of the law. And let's be honest here, a good screwdriver is more effective than a combat knife. Of else they would have continued to use daggers during the middle ages. People back then really KNEW how to kill each other without firearms, because this was considered to be an art as well as a professional career, and also a necessity in daily life, as there was no police.