Annoyed by teenagers 'hanging around' your shop / home / bus shelter / garden of remembrance? Fed up with their smell ? Their behaviour ? Their rat-like faces ? Then simply invest in a Mosquito. This invention, described in a CNet article here, makes a high-frequency noise which only yoofs can hear. It drives them nuts, apparently. The article also mentions other anti-yoof devices, such as the 'zit lamp' - this gives off a kind-of ultraviolet light which accentuates the visibility of facial pustules. This also annoys the yoofs. It will come as no surprise to you that I am all in favour of these kinds of things - now if someone could do something about the B.O. and rodent features....
Thanks to Cambridge News for the piccy, btw.