A re-ignition of the Civil War in 1925 in a manner that gets very, very dirty (perhaps the murder of the comparatively moderate elements of the two sides) and reduces Ireland to a 'failed state' situation worse than Spain in 1939 (perhaps ten years of massive large-scale domestic bombings and murders of scores of young men would achieve that), Britain can occupy it in the 1930s or, post-Emergency, as part of a reincorporation plan that comes into effect under plans set out at Potsdam.