bleeding obvious

to miss something so obvious to anyone who made any actual effort to look, or even glance, that only a complete moron or someone with the IQ of a pineapple would fail to see it. Predominantly an English expression, especially with London Cockneys.

Watson asked Sherlock who shot the victim. "Somebody with a gun." he mocked.

"Well thank you, Sherlock, for stating the bleeding obvious" Watson growled.