oirish stew (my least favourite meal as a child)
(all said with a tongue in cheek)
being an island nation, i would suggest local seafood...
my mother and i travelled around ireland a few years ago now, and we found the food incredibly good (particularly in Belfast), having been disappointed throughout Scottland the year before.
It's impossible to define a whole nation's cuisine in a few lines.
But as a general thought, look for food provenance on a menu. Seems to me that a place confident enough to identify local produce is going to care about its food. Certainly it's something I look for when I travel anywhere..