In 2013 the Flood began, and with it the European Refugee Crisis that drove millions from their homes and into the lands of their fellow Europeans. Well over half of Europe's population was forced into the interior of the continent, Eastern Europe, Scania, Spain and the Alps becoming the largest refugee centers.
The European exoduses were the largest migrations the continent has ever seen, and dramatically reshaped European society and culture. Prior to the Flood, Europe was united only by the EU and NATO, both organizations left several states out. With centuries of bitter rivalries, wars, and various conflicts between them, the EU as it was was considered nothing less than a miracle by some. The demographic mixing that Europe's Flood Generation experienced united cultures in a way that Europe had not seen since the time of the Roman Empire. the British isles, largely left inhospitable by the flooding drove most of the British population to Scandinavia and France. The Germans also found themselves sharing their country with refugees from Poland and visa versa. Most of the French refuges took shelter in Northern Spain or the Alps, while most of the Italian refugees were calling Croatia and Austria their home.
The Refugee Crisis is ultimately what drove the majority of European politicians to unite behind the creation of the European Federal Union after the Second Treaty of Maastricht. The creation of the Union was the tipping point for many in the less willing members of the EU, and a number of countries opted out in favor of more culturally specific unions. However, of those countries that did join, several experienced internal revolt and in the case of Ireland outright revolution over the formation of the Federation.
So began the European Unification War, a conflict that threatened the survival of the Federation, and the lives of countless people. While Italy, Greece, and France all experienced break away regions, the fighting was no worse than in the British Isles. Scotland, Wales, Ulster, and Ireland all entered into radical nationalist regimes following the Second Treaty of Maastricht, and along with fighting the "European Oppressors," they also fought internally. The War lasted from 2014 to 2018 and finally ended after the IRA backed government of Ireland was overthrown by the Union Party that advocated joining the Union as an autonomous region.
By 2033 the regions bordering the British Isles were largely english speaking, while german had spread throughout central Europe.