Neds (2010) on Netflix

Despite having a drunken, abusive father and a brother who leads a local gang John McGill is a studious boy for whom a bright educational future seems to beckon. However his studiousness isolates him and when he is invited to join the gang it gives him a sense of belonging. However he becomes increasingly more violet, stabbing a boy in the neck, for which his brother is blamed and jailed, and dropping a breeze block on a rival gang leader, causing him permanent brain damage. John is temporarily thrown out of his home by his mother and suspended from school though when he is readmitted he is placed in the remedial class. John now has no interest in education but in being the top boy amongst the NEDS or non-educated delinquents. He is invincible, and even the lions at the local safari park let him pass without attacking him.