OOC Clarification
Britain changed radically in the early years of the century - undergoing huge constitutional reforms and abolishing its monarchy, for most of the past century, the country has defined itself as a Social Democracy.
Ireland seceded, as a whole entity, early in the century, (and apparently became a kingdom - becoming a refuge to the disinherited British royalty?). Much to the consternation of many Irish. The North was a hotspot of anti-Free State activity, and civil strife was widespread. The North is governed from Dublin as a special province, under a semi-permenant state of emergency.
The *Central Powers won the *Great War, as referenced by the continuous existence of the German Empire. There were then two more 'Great Wars'. After these wars, the world was left divided between two ideological camps, the National Positivist United Nations, (USA, Germany, Ireland, etc.), and the Social Democratic International Conference, (Britain, France, Russia, etc.).
Antipathy is widespread between members of these two blocs, which serves to make creating a peace between Ireland and Britain very difficult. The Northern Ireland conflict is thus much more ideologically based than OTL, sectarianism is still a factor, but is overshadowed by the issue of whether one is a National Positivist/pro-Irish or Social Democratic/pro-British.