'Consistent with that notion, research suggests that areas that saw significant influx of migration from Eastern Europe following the accession of 12 mainly Eastern European countries to the European Union in 2004 saw significant growth in support for UKIP and more likely to vote to leave the European Union.Academic research investigating differences in Brexit vote among local authorities concluded that the Brexit vote was bigger in areas that had seen a large rise in the proportion of immigrants between 2004 and 2011.