begging your pardon, but (something)

I believe you are mistaken or incorrect; I beg to differ; I don't agree with you on that. Begging your pardon, but I believe you'll find that our school is actually one of the best in the state. Begging your pardon, sir, but the medical research we're doing is vital to society and warrants continued funding! A: "I just don't see the need to keep him." B: "Begging your pardon, but he's great defensively and wreaks havoc on the basepaths. I know he's not a big hitter, but I think releasing him would be a mistake."