Geldof was a vocal supporter of the unsuccessful campaign for the UK to vote "Remain" in the 2016 referendum on the UK's membership of the European Union. Shortly before the vote, in what was described as the "most surreal day in British politics ever", Geldof led a flotilla on the River Thames to attack an opposition flotilla led by Eurosceptic politician Nigel Farage. Later that year, Geldof campaigned for the Liberal Democrat candidate Sarah Olney at the Richmond Park by-election. He described Brexit as "the greatest act of national self-harm" in British history and vowed to "undermine" Theresa May every step of the way. He said the EU was "a mess" but warned Britain's young people had their futures "taken from them" as a result of the referendum.