The British Army was initially deployed , at the request of the unionist government of Northern Ireland , in response to the August 1969 riots . Its role was to support the Royal Ulster Constabulary ( RUC ) and to assert the authority of the British government in Northern Ireland . The main opposition to the British military 's deployment came from the Provisional Irish Republican Army ( IRA ) . It waged a guerrilla campaign against the British military from 1970 to 1997 . Catholics welcomed the soldiers when they first arrived in August 1969 , but Catholic hostility to the British military 's deployment increased after incidents such as the Falls Curfew ( 1970 ) , Operation Demetrius ( 1971 ) , the Ballymurphy Massacre ( 1971 ) and Bloody Sunday ( 1972 ) . An internal British Army document released in 2007 stated that , whilst it had failed to defeat the IRA , it had made it impossible for the IRA to win through violence , and reduced substantially the death toll in the last years of conflict
Bloody Sunday
Bloody Sunday (1972)
Operation Banner