One of the videos depicts teenagers setting ablaze various parts of their own clothing, another shows giggling youth creating fiery explosions, while still more feature boys dousing various objects with accelerants before gleefully igniting them.“It’s no good unless someone gets hurt,” concludes a participant in one.

YouTube is replete with such home-made, widely viewed clips portraying dangerous fire-setting behaviour — which a new Canadian study suggests might be exacerbating an already serious arson problem among young people.