Boris Johnson was the Mayor of London during Monos' graffiti attacks on London landmarks in 2012. When he gave a statement to the press on BBC News, he promised that the miscreant would be sorry for his actions. (COMIC: Sticks & Stones) Annie jokingly referred to the Russian mercenary Grigor as "Boris-not-Johnson". (AUDIO: And You Will Obey Me)
By 2020, Johnson was the Prime Minister of the United Kingdom. He was kidnapped by Sorb and Sarg and stored on their ship. Lucy Wilson and Hobo Kostinen later freed him along with the rest of the human race. (PROSE: The Edge of Glory) He was not Prime Minister on 1 January, 2021, as Jo Patterson won an election and was elected, but was soon killed by the Daleks after refusing to surrender to them. (TV: Revolution of the Daleks)
Behind the scenes
Boris Johnson's likeness appears on a gigantic humanoid machine which chases the Eleventh Doctor and Alice Obiefune in the 2017 comic Remembrance. This machine lives on the planet Britzit-247 alongside a bloodthirsty horde of individuals resembling Nigel Farage.
After Prime Minister Boris Johnson announced the assembly of four new committees to coordinate various aspects of the COVID-19 outbreak that would report their work in daily meetings dubbed "C-19 meetings", some media outlets reported the reaction of Doctor Who fans who noted a similarity between that of the sinister Department C19.
Russell T Davies for the Doctor Who: Lockdown! rewatch wrote Revenge of the Nestene, in which the last trace of the Nestene Consciousness merges with someone blonde in Westminster. It is implied that they are Boris Johnson, who in 2005 was an MP.