Brexit was incited by Russian disinformation & right wing elites weaponizing anti-migrant bigotry.
https://www.independent.co.uk/news/uk/politics/brexit-racism-immigrant-prejudice-major-factor-leave-vote-win-study-a7801676.html
https://www.vox.com/2016/6/25/12029786/brexit-uk-eu-immigration-xenophobia
https://tmg-uk.org/news/brexit-anti-immigrant-prejudice-and-voting-patterns
https://www.bbc.com/news/uk-37193140
As Heather McGhee's book "The Sum of Us" describes, bigots are willing to give up a lot to keep something as useful as bigotry alive.
Give up the bigotry & Russia's "divide & conquer" lies loses its efficacy.
https://www.theguardian.com/commentisfree/2020/jul/21/russian-meddling-brexit-referendum-tories-russia-report-government
https://en.m.wikipedia.org/wiki/Russian_interference_in_the_2016_Brexit_referendum
https://www.csis.org/blogs/brexit-bits-bobs-and-blogs/did-russia-influence-brexit