Afterwards the boy is seen stalking around the cell and throwing his torn-up mattress at the CCTV camera in visible distress.
The assailants, who appear to be teenagers, also throw soda cans at the child, who crouches on the floor in a defensive position.
Following the discovery, Mrs and Mrs Aughterson approached the school with the footage â where they were redirected to the bus company, Crown Coaches, who own the bus where the sexual assault occurred.