Photo: IC

British Prime Minister Boris Johnson threatened to expel rebel lawmakers from his Conservative Party if they thwart his Brexit plans by voting to prevent a no-deal exit from the European Union.

Johnson's promise to leave the EU on October 31 with or without a divorce agreement has propelled the UK towards a constitutional crisis and a showdown with the 27 other members of the bloc, with an election one of the possibilities.

Conservative Party rebels are plotting with opposition parties to take control of parliament and tie the government's hands with legislation that would block a no-deal exit from the EU which they say would be ruinous to the economy.

With just over 24 hours until parliament returns on Tuesday from its summer break, Johnson's enforcers warned rebels that if they voted against the government they would be giving control of parliament to Labour Party leader Jeremy Corbyn.

"If they fail to vote with the government on Tuesday they will be destroying the government's negotiating position and handing control of parliament to Jeremy Corbyn," said a source in the whips office, which is responsible for party discipline.

"Any Conservative MP [member of parliament] who does this will have the whip withdrawn and will not stand as Conservative candidates in an election," the source said.

More than three years since the United Kingdom voted 52-48 percent in a referendum to leave the European Union, it is still unclear on what terms, or indeed whether, Brexit will take place.

Corbyn, Labour's veteran socialist leader, will say on Monday he is ready to do everything possible to stop a no-deal Brexit, describing it as a final attempt to pull "our country back from the brink."

In the parliamentary chess game over Brexit, it is also unclear what Johnson's response will be if the alliance of rebel Conservative lawmakers and opposition parties succeed in defeating the government.

Johnson, the face of the 2016 Vote Leave campaign, has cast rebels as EU "collaborators" who are undermining the government's negotiating hand by blunting his threat of a no-deal Brexit.