Playing heavily and superbly on the British aversion to the "hoodie-wearing yobbos" the media is telling us we must fear, Johannes Roberts' movie is a violent, underrated stalk-and-slash gem following a group of teachers - led by the disaffected, alcoholic paranoid loner amongst them that they all despise - who must defend themselves from a gang of murderous kids when their school comes under siege after hours. It's not a perfect film by any stretch of the imagination, but it is a thrilling and very well-made genre entry. See this if David Moreau and Xavier Palud's Them or Alexandre Bustillo and Julien Maury's Inside were your sort of thing!