Despite being a 'remain' advocate, Benedict Cumberbatch only agreed to do the film after he had been assured by James Graham, who wrote Brexit: The Uncivil War, that it is not going to end up being just a 'pro-EU stitch-up.'
Various parts of Ludwig van Beethoven's Ninth Symphony appear prominently as the film's soundtrack. This is clearly symbolic: the main theme of the work's Finale, the well-known "Ode to Joy," is also the music of the official anthem of the European Union. The music for the concert attended by Craig Oliver and Boris Johnson in the film is also the Ninth Symphony.
There are references to O Espião Que Sabia Demais (2011) and the Avengers movies from the Marvel Cinematic Universe. Benedict Cumberbatch has worked in both.
The painting featured in The Tate Britain gallery is The Death of Major Peirson by John Singleton Copley.
During the meeting between Dominic Cummings (Benedict Cumberbatch) and Zack Massingham (Kyle Soller), they stand in front of a statue representing Europe (Albert Memorial, London). This film talks about the separation of Britain and a European institution--the EU.