LONDON (AP) — Britain’s opposition parties are intensifying attacks on Prime Minister Boris Johnson with two weeks to go until election day, as polls suggest Johnson’s Conservatives have a substantial lead.

Jo Swinson, leader of the opposition Liberal Democrats, was using a speech Thursday to say Johnson has dragged the office of prime minister “through the mud.”

The party says Swinson will argue that “you cannot trust a word Boris Johnson says,” because he vowed to lead Britain out of the European Union by Oct. 31 — and didn’t — and said he would never ask the EU to delay Brexit, but did.

Britons will vote Dec. 12 to fill all 650 House of Commons seats. Johnson says that if the Conservatives win a majority, Britain will leave the bloc on Jan. 31.