LONDON — Prime Minister Boris Johnson is preparing to call an election, British media reported on Monday, on the eve of an historic showdown with parliament over Brexit.

Johnson's promise to take the country out of the European Union on Oct. 31 with or without a deal to smooth the divorce between the world's fifth-largest economy and its biggest trading partner has propelled the United Kingdom toward a constitutional crisis and a battle with the 27 other members of the bloc.

An alliance of opposition lawmakers are plotting with rebels in Johnson's Conservative Party to take control of parliament and tie the government's hands with legislation that would block a no-deal exit, fearing leaving without a deal will be ruinous.

Just 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 kicked out of his Conservative Party.

With little clarity on whether the deadlocked British parliament might be able to come up with a resolution to the three-year Brexit crisis, talk turned to a possible election.

"We want a general election," opposition Labour Party leader Jeremy Corbyn said, to oust Johnson's "phony, populist cabal".

He added: "We must come together to stop no deal — this week could be our last chance."

However, former Labour Prime Minister Tony Blair warned Corbyn, a veteran socialist, to avoid what he cast as an election "elephant trap" Johnson had laid for Labour.

"Boris Johnson knows that if no-deal Brexit stands on its own as a proposition it might well fail but if he mixes it up with the Corbyn question in a general election he could succeed despite a majority being against a no-deal Brexit because some may fear a Corbyn premiership more," Blair said.

Johnson has called a Cabinet meeting for later on Monday and could ask lawmakers to vote on calling an election if they vote against his government on Brexit, the BBC's Political Editor Laura Kuenssberg said.

The Sun newspaper's political editor Tom Newton Dunn also said Johnson was preparing to call an election.

Asked if Johnson was planning an election, his spokesman said: "He has been asked this on many, many occasions and his answer has always been that he doesn't want there to be an election."

After winning the top job in the chaos that followed the 2016 EU membership referendum, then Prime Minister Theresa May bet on a 2017 snap election but lost her majority.

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

In the parliamentary chess game, the default position is that Britain will leave on Oct. 31 without a deal unless a divorce agreement is struck with the bloc and ratified by the British parliament or legislation is passed to delay or revoke the departure notice.

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

"Their (the government's) strategy, to be honest, is to lose this week and then seek a general election," said David Gauke, a former justice minister who is one of the rebel Conservative lawmakers.

Jacob Rees-Mogg, the minister responsible for parliamentary business, said any wise party would prepare for an election and that any vote on rebel legislation would be considered a matter of confidence in the government.

"It is important for the government to establish the confidence of the House of Commons and this is essentially a confidence matter: Who should control the legislative agenda, Jeremy Corbyn or Boris Johnson?" Rees-Mogg said.

An election would open up three main options: a Brexit-supporting government under Johnson, a Labour government led by Corbyn or a hung parliament that could lead to a coalition or minority government of some kind.

After Johnson moved to suspend parliament ahead of Brexit, opponents of a no-deal exit are seeking to overturn his decision in the courts. Hearings are due on Sept. 3, Sept. 5 and Sept. 6.

Nick Boles, a former Conservative who now sits as an independent member of parliament, said the rebels would seek to force the government to ask the EU for a Brexit delay if it was unable to ratify a revised Withdrawal Agreement by a certain date in October. — Reuters