The head of Britain's domestic intelligence agency MI5, Ken McCallum, confirmed that Russia did try to interfere in the Brexit referendum, through social media and television reports, but said that did not mean the Kremlin had any impact on the result.

In an annual threat update, McCallum said RT and Sputnik, Russian-owned English-language broadcasters, came in strongly around the time of the referendum with biased anti-migration and anti-EU reports, and cited trolls with fake accounts. Downing Street said it had been confirmed that Russia interfered in the 2019 general election and that it was “inconceivable that they didn't in 2016”.