Gang violence can be explained by the social identity theory. Members of a gang will form an in-group and other members of society or of a rival gang will form the outgroup, this is known as social categorisation, such as the Ladbroke Grove Boys (LGB), who are based on the Kensal New Town Estate, and the Harrow Road Boys (HRB) from the Mozart Estate. Secondly, Social Identification occurs, where the individual adopts the beliefs, values and attitudes of their ‘in-group’ and behaves in accordance with the norms and values of a group. For example, members of a gang might adopt gang tattoos, such as rosary beads with a cross on the hand a heart with £ or $ on the hand. As well, members of a gang may carry a knife or a weapon.