It waged a limited campaign against the British Army , mainly involving shooting and bombing attacks on troops in urban working-class neighbourhoods . Most notably , it was involved in the 1970 Falls Curfew and carried out the 1972 Aldershot bombing . In May 1972 , it declared a ceasefire and vowed to limit its actions to defence and retaliation . By this time , the Provisional IRA had become the larger and more active faction . Following the ceasefire , the OIRA began to be referred to as " Group B " within the Official movement . It became involved in feuds with the Provisional IRA and the Irish National Liberation Army ( INLA ) , an OIRA splinter group formed in 1974 . It has also been involved in organized crime and vigilantism
1972 Aldershot bombing
1972 Aldershot bombing
Official Irish Republican Army