This became the subject of discussion when in September 2015, then-current Prime Minister David Cameron was alleged to have placed his penis into the mouth of a dead pig as part of a university initiation rite (with even some of the hashtags seen in this episode being used).
Charlie Brooker stated in an interview that he went 'all through the farmyard' deciding what animal Callow would have sex with and even briefly considered a block of cheese. Also considered were a duck or a chicken (both of which were rejected as it was thought their small size was too absurd), a horse or a donkey (the horse and donkey being rejected as they were deemed too difficult to film with). A pig was eventually chosen as it was deemed to '[straddle] the line between comic and horrifying'.
In an interview, Hugh Grant revealed that he turned down the role of the Prime Minister due to scheduling.
At around 16:43, a group of nurses discuss some rules and cinematic movement and mention Lars von Trier. Two years later, Sophie Kennedy Clark, one of the nurses, starred as B in Nymphomaniac: Vol. I (2013) and Nymphomaniac: Vol. II (2013), both directed by Lars von Trier.
One character mentions that an actress being interviewed on TV had appeared on Downton Abbey (2010). Allen Leech, who plays Pike in this episode, plays a main character (Tom Branson) in Downton Abbey (2010).