I am not a lawyer, but two factors that enter into it are: circumstances, and intent.   If you are a chef heading to your first day of work, and police stop you with a securely tied up roll of 10 kitchen knives in your bag, then you have a reasonable and lawful purpose to be carrying knives.   If however, you are heading out to the pub at 10pm on a friday, and you have a knife in your coat pocket, then that is an entirely different story.  Same thing with screwdrivers and other potentially offensive weapons.   Carrying a stick of wood home from the garden centre is different to taking a baseball bat to a nightclub, or being arrested with one in your hand after a fight, and the law recognises that.    188.220.45.209