Reviewed by GREG KING Director: Yann Demarge Stars: Jack O'Connell, Sean Harris, Richard Dormer, Sam Reid, Charlie Murphy, Killian Scott, Barry Keoghan. Sectarian violence erupted in Northern Ireland in the early 70s as the bitter conflict between Catholics and Protestants began to spiral out of control. British troops were sent in to try and maintain an uneasy peace. Amongst the green and inexperienced squad …