Conservatives celebrate their biggest win since Margaret Thatcher. Boris Johnson promises Brexit, and a life after it. The Conservative victory buoyed the pound and stocks. With all districts declared, Prime Minister Boris Johnson’s Conservatives had won 365 seats — 48 more than they won in the last election, in 2017. The prime minister said it would give him a mandate to “get Brexit done” and take the UK out of the EU next month. Labour, which has lost seats across the North, Midlands and Wales in places which backed Brexit in 2016, is facing its worst defeat since 1935.