 Shearsmith said that the episode 's focus on a grandmother 's birthday party felt " domestic " and " homely " . Pemberton , too , called it a " domestic " story , describing it as playing upon the classic British plot device of a family party going wrong . Shearsmith suggested that the pleasant house did give the episode the feel of a sitcom , but said that the story went somewhere " darker " than a typical sitcom would . With " Nana 's Party " , the writers wanted to produce something " dark " and " suburban " , with Pemberton citing the playwright Alan Ayckbourn as an influence . Indeed , at the time the episode was written , Shearsmith was starring in an adaptation of Ayckbourn 's play Absent Friends . 
