Firefighters were called in to put out a fire in a Swindon town centre park on Tuesday.
A group of around twelve teenagers were witnessed setting fire to twigs, branches and deodorant cans from nearby trees int he middle of the main field at Queens Park at around 6pm.
A number of small explosions were heard as the cannabis-smoking youths risked a major grass blaze while committing their arson attack.
One fire crew from Royal Wootton Bassett, who were on standby in Swindon, attended the scene and extinguished the small fire using their feet and buckets of water.
A police officer was also called to the scene, giving words of advice to the teenagers.