This is the 3rd time he's actually hit someone hard enough to leave a mark. Has generally always been a "challenging" child, who pays very little attention to authority and has very little impulse control. In this case, the child pushed him so he whacked him with a wooden hoop - unfortunately headmistress saw it! I have told him over and over again no hitting, pushing and fighting but he plays with a group of boisterous boys and they seem to spend all their time doing this - and he is one of the worst. I can't think what to do - already constantly telling him off at home, and removing dangerous objects from his grasp. But he just seems to spend his whole time pretend fighting and battling - it's wearing me down! We went on holiday with a group of families and spent the whole time supervising and pulling him away from fighting the other boys on the trip (who were bigger but less vicious). We have already removed sweets and chocolate from his diet and tried to ensure he gets lots of sleep. Any ideas?