Originally Posted by Wikipedia, the online encyclopedia
There is a unique body of English ritual and etiquette surrounding the consumption of port, stemming from British naval custom.
Traditionally, the wine is passed "port to port" -- the host will pour a glass for the person seated at their right, and then pass the bottle or decanter to the left (to port); this practice is repeated around the circle.
If the port becomes forestalled at some point, it is considered poor form to ask for the decanter directly. Instead, the person seeking a refill would ask of the person who has the bottle: "do you know the bishop of Gloucester?" (or some other English town). If the person being thus queried does not know the ritual (and so replies in the negative), the querent will remark "He's an awfully nice fellow, but he never remembers to pass the port".