Antisocial behaviour

Teenagers may text each other ceaselessly on mobile phones and post their latest news on social-networking websites, but electronic gadgetry is no substitute for the buzz of hanging out with the gang. Over the past 18 months, however, a different sort of buzz has been used to disperse young people who gather outside shops or public buildings. When Howard Stapleton's daughter was bullied by a group of youths outside a shop in Wales, he invented a device that emits sound at a frequency which is very irritating to people under 25, but inaudible to nearly everyone above that age. Thousands of shopkeepers and local authorities have since bought the devices - called Mosquitoes, because they sound like a very loud insect.