Very interesting replies.

Most of my travel is within the EU and yet I am required to show my passport at my point of origin and my destination.

The checks take longer since the terror threat ramped up. Previously I would just wave the cover of my EU passport at the immigration official and get passed through. Now they examine it and check it with their database as well.

So if I, for argument's sake, am an undesirable person under UK law I can board a plane to Dublin from NY and be happy that I can get into UK without detection?