For many years now I've had in my memory this scene from star trek tng where, for whatever reason, a group of British officers and Irish officers led by O'Brien start getting nationalistic and sing their respective national songs at each other. I remember the British were singing "Rule Britannia" but I don't recall the Irish song.

Writing this out it sounds bizarre and I'd almost think I dreamt it up but I couldn't come up with these details. I might have seen it somewhere else but i distinctly recall O'Brien. Does this sound familiar to anyone else? If indeed this is real, what episode?