In 1970 Stone helped establish a Braniel street gang, which called itself the Hole in the Wall Gang, and which Stone claims included Catholic and Protestant members. Gang members, who adopted a form of uniform consisting of blue jeans and oxblood Dr. Martens and who carried knives, clashed regularly with members of other Braniel gangs as well as those from neighbouring estates in east Belfast. In 1971 Stone joined a "Tartan Gang" that had started up on the Braniel estate and he was soon recognised as "general" of this loyalist group. The gangs were responsible for sectarian violence, which usually took the form of spending Saturday afternoons in Belfast city centre attacking Catholic youths, and vandalising the Catholic repository in Chapel Lane.