Your thirteen year old son Sam is an adventurous athletic boy. He will have a go at any sport but his chosen one is boxing and he has a few trophies on a shelf in his room. Basically he is a good kid you are proud of but he is prone to keep testing the boundaries thus is still subject to spankings and an occasional encounter with the strap.
This Saturday afternoon he has gone down to the park with a couple of his friends for a kickabout. Some time later when you take the dog down there for a walk you spot a disturbance amongst a group of youths and see Sam standing over another boy on the ground. You walk across unnoticed to find a boy who is rather bigger than Sam and looks older sitting nursing a bloody nose and a split lip, possibly also with the beginnings of a black eye. Sam is standing over him challenging him to get up. The fury in Sam's face and the venom of his challenge alarms you and you take a firm grasp on his arm and lead him away from the fracas.
Sam is so wound up and angry that he is unable to respond coherently to your demand for an explanation but his friends explain that there had been bad blood between Sam and the other boy who had a reputation as a bully, that recently the boy had started putting it round that Sam didn't know who his real father was because his mother was a whore. When Sam spotted him in the park he went across to confront him but the other lad just sneered at him, told him to f**k off and gave him a violent push.
Your hand released its grip on Sam's arm and moved up to rest on his shoulder. At this the adrenaline suddenly stopped pumping and he clung on to you as he dissolved into tears.
How do you proceed from here?