What's that got to do with the price of cheese?

What's that got to do with the price of cheese?

A rhetorical question calling attention to a non-sequitur or irrelevant statement or suggestion made by another person. Primarily heard in UK. Yes, I agree that health care is an important issue, but what's that got to do with the price of cheese? We're discussing tax incentives for local businesses—not exactly a related topic!See also: of, price, that