What one is supposed to say in an authorative Cockney accented voice if they are greeted with "'Ello 'ello" (or "Hello hello" in a Cockney accent). Is taken from the policeman character Graham Chapman used to play regularly on the TV show Monty Python's Flying Circus. Chapman would barge into the setting (sometimes in the middle of a sketch), and demand to know "What's all this, then!?"