UK, Ireland /
EU integration of Polish nationals in the UK vs no surrender [43]
England is very different from Northern Ireland in this respect. I hope to be able to speak for all of England (something I don't usually presume to be able to do), that any kind of Protestant - Catholic divide is ancient history and these days it is a non-story.
Northern Ireland protestantism is dominated by Presbyterianism, whereas in England it is dominated by the Church of England (much closer to Catholicism) and it is far more diverse. The scene in Scotland seems to be a little closer to Northern Ireland, but certainly without nearly as much of the trouble. Wales is quite mixed in different forms of Protestantism and Catholicism.
The "troubles" in Northern Ireland are so deep-rooted and complicated (despite the very simple brains of many who get involved), that a simple look at who follows which branch of Christianity merely scratches the surface.
The Roman Catholic church is, I believe, the fastest growing church in the UK, and not just from Polish migrants as someone once stated on this 'ere forum. In Northern Ireland, this would be accounted for by the faster growing Catholic population. (See the "Every Sperm is Sacred" song from Monty Python's Meaning of Life.)