Samuel L Jackson gives a sterling performance as a high-school science teacher who survives a stabbing in New York, starts again at another school in LA, only to be tipped over the edge by what he finds there into vigilantism.

Sadly, though, Jackson's performance is the only thing to commend this movie - certainly its hysterical tone, overheated plotting, bizarre characters and unpersuasive dialogue won't help make it anyone's favourite movie.

Are schools really like this in the USA? We sure hope not!

Marks for credibility: one point eight seven out of ten.