(FILES) People march with EU flags and pro-Europe slogans on placards during a March for Europe protest against the Brexit vote in London on September 3, 2016. June 23, 2026 marks 10 years since the UK voted for Brexit, upending the country's politics and triggering fraught negotiations that finally concluded when it left the European Union in January 2020. Immigration, trade and the economy were all key issues during the Brexit campaign. (Photo by JUSTIN TALLIS / AFP via Getty Images)