A teacher shouted 'Die, die, die' as he bludgeoned a 14-year-old boy with a metal dumbbell after being baited by an unruly class of teenagers who were secretly filming him, a court heard today.

Peter Harvey, 50, eventually 'snapped' after the boy 'lit the blue touch paper' by telling him to 'F*** off'.

A jury heard how the science teacher then dragged the boy out of a class and across a corridor before hitting him twice over the head with the 3kg weight.