 The aim is to be the first to announce "Mornington Crescent", a station on the Northern line.Interspersed with the turns is humorous discussion amongst the panellists and host regarding the rules and legality of each move, as well as the strategy the panellists are using.Mornington Crescent first appeared in the opening episode of the sixth series of "I'm Sorry I Haven't a Clue", broadcast on 22 August 1978.