The Liberal Democrats stormed to victory in London as Labour lost half their seats and the Conservatives were wiped out.
The Lib Dems won the popular vote over the city, including in key Labour and Tory-voting areas, taking three of the region’s eight seats in the European Parliament.
Speaking on Monday afternoon, party leader Vince Cable said his party's success at the ballot box shows it there is a clear national interest in stopping Brexit.
After a tough few years for the party, which saw it lose the majority of its MPs, Mr Cable said the result of the European elections shows the Lib Dems are once again a "major national force".
Labour won two, down from four in 2014, the Conservatives lost both their seats while the Brexit Party gained two, the Greens retained one and Ukip lost one.
A jubilant group of Lib Dem supporters dressed in yellow cheered and hugged shortly before the result was officially announced at London City Hall.
Irina von Wiese, Dinesh Dhamija and Luisa Porritt will now serve as MEPs for the party.
One of the Lib Dem victories was in Jeremy Corbyn’s borough Islington, where the party beat Labour into second place.
A London Labour Party spokesman said: “These elections were always going to be tough for Labour in London, set in a polarised environment for both sides of the Brexit debate.
“We’re ecstatic that both Claude Moraes and Seb Dance have been elected as MEPs for London.
“Our MEPs will go to Brussels championing workers rights, fighting climate change and the other issues important to our party.”