The teenage girl in the video was indignant about the way adults typecast young people. We don’t cause trouble, she said - only when we’re defending our territory. She was responding to a couple of older people who were voicing their generation’s usual complaints - run-down estates, graffiti and ‘gangs hanging around causing trouble’. The occasion was the last in a series of ‘Steel City shorts’ made by a group of Sheffield teenagers for the BBC. Broadcast to mobile phones across the city centre, they described youngsters’ experiences of city life.