Boris Johnson, frontrunner to be Britain's next prime minister, promised Monday to lead the country out of the European Union on Oct. 31 with or without an exit deal, launching his leadership bid in a campaign video.

Prime Minister Theresa May is due to resign Friday having failed to deliver Brexit on schedule. She leaves behind a divided nation and Parliament with no consensus on the way ahead for the world's fifth-largest economy.

Johnson, a former foreign minister who resigned in protest at May's handling of Brexit, is the bookmakers' favorite to win a crowded contest and take over the running of the country at its most important strategic juncture in decades.