A primary school student was slapped and beaten with a belt by his father in front of his classmates and teachers in Sha Tin yesterday. Ng Kin-ying, 12, escaped serious injury when his teacher stepped in to stop the attack by the 68-year-old father in the Cheung Wong Wai Primary School playground in Sun Chui Estate. The boy was treated for arm and leg injuries at Prince of Wales Hospital and was accompanied by a social worker. The attack began at about 8 am as students gathered in the playground for morning assembly. The father, who went to the school to take items Kin-ying needed for his graduation camp, became angry when he suspected the boy had sold some of his Gameboy computer game cartridges. He lost his temper, slapped his son's face and then took off his leather belt to whip the boy, a Primary Six pupil. A school worker said the father stopped when a teacher approached and shouted, after which he left. The boy grew up without his mother in Sun Chui Estate. The boy's father went to Tin Sum police station last night and was told to return today.