Billy Connolly tells of when Mario Lanza was playing The Glasgow Empire, and a drunken heckler kept shouting "Sing "Softly Softly" it's my Mum's favourite." After lots of "I don't know that one" and getting impatient with the heckler, he apologised to the audience and said "I DO NOT KNOW SUCH A SONG. DO YOU UNDERSTAND?"

The bloke shouted "Well show us your cock then."