brutal clip shows a teenage girl being repeatedly punched to the head by another girl on the backseat of a bus while a group of the attacker's pals laugh in the background.The aggressor wearing a white jumper is seen to punch and kick her victim as the youngster cowers in the corner of the bus.Close to the end of clip her shrieking pals are heard to shout out comments like "That's it now, leave it - that's it, leave it."A second vicious 40 second video features two teenage boys punching each