Although it had already been confirmed in 2006 that the show was not being recommissioned, a change in the law in the UK in 2007 banned indoor smoking in the workplace, meaning the existence of a smoking room would be illegal.
Creator Brian Dooley revealed in the DVD commentary that he based the character of Robin on himself and the character of Sally on a close friend. He also confirmed that some of the other characters featured "elements" of people he knew in real life, but was deliberately non-specific, stating that his friend would be flattered to find out that Sally was based on her, but that others might not feel the same about less likeable characters.
The show makes heavy use of unseen characters, partly because of its single location setting. Tess Pownall, Lucy Wu, Rangit and Heidi's husband Keith are the most frequently referenced characters. The character of Ben from the postroom - the object of Robin's not-so-secret love - is unseen in the sense that viewers are never shown his face, but he does appear on screen twice; once in a snowman costume, and once shown only from behind, when he is voiced by series creator Brian Dooley. The DVD boxset of the show features a series of drawings by Dooley depicting the unseen characters.
Manager Sharon's cigarettes are always much longer than those seen smoked by her subordinates.
The character of Robin is present in the smoking room throughout every episode, even if he does not appear on screen during a scene. Lilian, Barry, Sally and Annie all appear in every episode, but they are typically shown entering and exiting the room at various points.