Anything can be classed as an offensive weapon - it's the
intent that's important. Depending on what you were planning on doing with it, a tea spoon, or even a pencil sharpener, could be classed as an offensive weapon! I always carry a decent penknife with me in the car and it's used (legally) daily...
I once asked a Hells Angel why he carried an axe with him on his bike and he said it was for chopping fire wood while camping, apparently
....