大不列颠及北爱尔兰联合王国是一个西欧岛国。It was first featured in the Season Four episode, "Pip". It later appeared in the Season Eleven episode, "The Snuke", when the United Kingdom military attempted to invade the United States.
In "The Snuke", the British attempt to invade the United States to deny America its independence, however they fail when United States Air Force jets fly in and destroy the Royal Navy. Queen Elizabeth II then commits suicide.
In "Members Only", Boris Johnson calls then-President-elect Garrison in a panic and warns him about the dangers of eating the Memberberries. Garrison, who is blatantly unreceptive, angrily disconnects the call with an insult to the British politician.
The British are portrayed as sailing in Revolutionary War era naval vessels. The Army is shown equipped with the outdated musket and wearing the standard 'red coat' uniform. However, modern technology such as mobile phones are still used by the commander of the fleet.
Britons are also seen as knowing all about castles, legends, and myths. Their clothing is archaic, including flat caps, Victorian style bolas ties, and red jackets.
- Britain's rivalry with France is referred to in the episode "Conjoined Fetus Lady", when Pip Pirrip is pressured into playing dodgeball.
- In Goin' Down to South Park, it's stated that South Park's popularity in Britain rivals its popularity in the United States.