Irish children of English immigrants who left Britain due to Maggie The Bitch Thatcher's Rise to power. Keeping their English accents and strong ties to England, they're often quite ignorant of Irish history and tend to be very clannish, living in lose communities, particularly in East Clare and West Cork.
A: Where are you from in England?
B: I'm frum West Cohhk Bruv.
A: Really? Don't sound it.
B:Grew up in Bantry mate.
A: Were your parents hippies that moved over in the 80s?
(probably best not to actually call them a Thatcher Baby unless you know them well)