Brexit

Brexit was something which the youth of 2016 considered to be unstoppable. (PROSE: What She Does Next Will Astound You)

In December 2016, after discovering that the Jezrafeq were controlling the minds of most of humanity, Andy Hansen jokingly asked Erimem, "You don't think this could explain Brexit and Donald Trump, do you?". Later, while tracing the source of the mind control signal, Andy suggested that the signal may have been coming from Trump Tower "because [Donald Trump] and Nigel Farage want[ed] to piss [Andy] off even more before the year end[ed]". (PROSE: Cliff Richard Saves the World)

On 5 May 2018, Alistair Gordon Lethbridge-Stewart read a news article about Theresa May being encouraged to pursue a "no compromise" Brexit after UKIP voters flocked to Tories in local elections. (PROSE: Lucy Wilson and the Bledoe Cadets)

Behind the scenes
Brexit is the United Kingdom's exit from the European Union.

The Doctor Who: The Eleventh Doctor comic story Remembrance provides a parody of Brexit in the form of the planet Britzit-247. The part of Britzit-247 seen in Remembrance is a city with elements reminiscent of London which is populated by individuals who all resemble angry Nigel Farages and only say the word "Britzit". There's also a giant robot with the face of Boris Johnson. The Eleventh Doctor explains that Britzit-247 was founded by a group of Britons who "got cross about something or other" and decided to "travel across the stars" to start their own independent colony.

In 2019, Resolution established that UNIT operations in the UK were suspended, pending review, due to financial disputes, and "subsequent funding withdrawal by the UK's major international partners". It was widely reported, following broadcast, that Resolution was here making reference to Brexit.

In the DWU, the UK is still explicitly part of the European Union in AUDIO: The Longest Night, when the British Prime Minister signs the Euro-Combine Treaty. Even in this storyline, though, many see the strengthening of the "European superpower" as a threat to the UK's independence.

The UK later belongs to the Eurozone in AUDIO: Hothouse and PROSE: Trading Futures; Trading Futures remains vague as to when exactly in the early 21st century it's set, but the after-credits segment of Hothouse places that story before the events of The Eight Truths in 2015.