The increasing violence in Derry and elsewhere led to increasing speculation that internment without trial would be introduced in Northern Ireland , and on 9 August 1971 hundreds of republicans and nationalists were arrested in dawn raids . In Derry , residents came out onto the streets to resist the arrests , and fewer people were taken there than elsewhere ; nevertheless leading figures including Seán Keenan and Johnnie White were interned . In response , barricades were erected once again and the third Free Derry came into existence . Unlike its predecessors , this Free Derry was marked by a strong IRA presence , both Official and Provisional . It was defended by armed paramilitaries — a no @-@ go area , one in which British security forces were unable to operate .