What is the difference between English and Irish Breakfast teas?
The ingredients are different and if so, is there really a marked difference in taste? Thank you for your comments:)

Both English and Irish Breakfast teas are black tea blends. English Breakfast tea is designed to complement fatty fried food and strong flavors (i.e. bacon, eggs, smoked fish). The Irish traditionally prefer a strong and dark brew. Comparing the two blends:
ENGLISH BREAKFAST
Usually contains Keemun (China), Assam (India), Ceylon
(Sri Lanka), and African teas
IRISH BREAKFAST
Usually a blend of rich, malty Assams and sometimes have
African and Indonesian leaves added.
In either case, the taste is primarily affected by the quality of the leaves used
for the blend itself. I hope you find a blend that suits you. Try them with/without milk and/or sugar. Enjoy the process!