This episode was broadcast live. It featured several in-jokes, including the cast seeing themselves when they turned BBC Three on their television, several comments about "jumping the shark", and Donna (Natalie Casey) performing the song "Chick Chick Chicken" which was the actress's first claim to fame when she performed it on TV as a two year old.
"Jumping the shark" is an idiom used to describe the moment of downturn for a previously successful TV-series or enterprise. Ralf Little thought, after 6 seasons, that the series was over its highpoint. He wanted out and the producers thought it a good way out to use the idiom of "Jumping the Shark" and that Jonny would be eaten by "said" Shark.