Student pranksters caused a school to be evacuated ahead of an exam after they set off a smoke bomb in the canteen.
Police arrived at Newent Community School in Gloucestershire at 1.15pm on Tuesday following reports of green smoke filling the school's cafeteria.
Pictures of the stunt were posted across various social media platforms, with accompanying messages suggesting the smoke bomb was the work of a departing student.
"Goodbye Newent School, I seem to think it's going to take you a while to forget about us," one poster wrote.
While a parent told their local paper they thought it was just 'typical end of school excitement' that had 'got a bit out of control', local councillor Len Lawton disagreed and said the cost to the emergency services in terms of other people's safety could have been great.
"These things might seem like a prank to some but there are very serious issues to consider," he said, adding that potentially pulling emergency services workers away from other incidents and the disruption to lessons was a 'serious issue'.
"It would be very unfair if people were taking exams at the time. That could have all sorts of ramifications. The people who have done it need to think carefully about how it affects others as it's very selfish," he said.
A Newent police spokesman said the school had not filed a complaint against the four boys responsible, and had put it down to a prank carried out because it was the end of school for some pupils.