When I was a teenager we lived outside of London, in Uxbridge, at the end of the Brown line (subway). In '71 skinheads were tough talking punks who preyed on the weak and/or foriegners, and they caught me alone on the tube on my way downtown one Saturday. Four of them accosted me with every intention of stomping me so I pulled a switchblade I'd bought in Calais for 20 Francs, ~$5 at the time. It was about a 4" stiletto type blade, an el cheapo kid's knife, never sharpened. One of them tried to kick the knife out of my hand and I jabbed it into the top of his foot, yanked it out and backswiped toward another one trying to encircle me. It was pretty tense for a minute or two until we got into another station and I bolted off the train. They didn't follow me, and I didn't ride the tube alone anymore. I sure as hell wouldn't want to ever get in a knife fight.