With all due respect
Said right before an insult, making sure the person is due none.
Wit all due respect, Father, ya couldn't referee a game of Snap.

Shall I translate it into posh English for you, sham?
Hello, hello, hello. Here it is in posh English.
With the greatest deference, Father, you could not adjudicate a game of Snap.
Questions
What does with all due respect mean in Ireland?
Said right before an insult, making sure the person is due none.
How do you use with all due respect in a sentence?
“Wit all due respect, Father, ya couldn't referee a game of Snap.”
Updated
On the list: Irish slang phrases