British Prime Minister Boris Johnson's office said his chief parliamentary opponent Jeremy Corbyn's behavior represented a "cowardly insult to democracy," in a statement on Thursday morning, after the Labour leader's lawmakers refused to endorse Johnson's demand for an election late on Wednesday night. That was the latest in a series of parliamentary defeats for the new U.K. premier that have restricted his options on Brexit. The lower chamber of the British Parliament, the House of Commons, had earlier on Wednesday evening advanced a piece of legislation to block the possibility of a so-called "no-deal" Brexit at the end of next month, a bill that Johnson insisted would deprive his negotiating team of a powerful form of leverage with the EU as his government seeks a more palatable version of Britain's existing exit agreement. Johnson said he wants an election on October 15 to win both a fresh public mandate and a legislative majority. He had repeatedly insisted such renewed support would allow him to push his European counterparts for a reworked Brexit deal days later at an EU Council summit scheduled for Oct. 17. And then regardless of whether an amended deal is struck or not, it would mean the U.K. could still leave the EU by the current Brexit deadline of Oct. 31. But Corbyn has indicated he does not want an election to take place before that Council meeting and the likely granting of a Brexit extension. He and other Johnson critics say a date close to or just after Oct. 31 could result in an "accidental" no-deal scenario, and they will only agree to a new election once a no-deal Brexit on October 31 has been definitely ruled out with fully-executed legislation. The current bill may be written into law as soon as Monday, say parliamentarians. Leader of the House of Commons, Jacob Rees-Mogg, has also confirmed that Parliament will again debate and vote on an early election the same day.

"We have to accept there will be an election at some point fairly soon, whether it's next week or a few months, it's going to happen," says Conservative Robert Hayward, a member of the parliament's upper chamber, or House of Lords, which will likely endorse the legislation that blocks no deal by Friday afternoon, just days before a five-week suspension of parliament begins. But Hayward and other legislators of all political stripes say a new election would prove highly unpredictable, because for the first time ever in British campaign history political parties might forge cross-party pacts over which constituencies they contest, so as to strengthen their respective positions on Brexit. And Hayward says voters may act in a similar manner, because the national popular vote is not always reflected in the final parliamentary arithmetic thanks to Britain's first-past-the-post system. "You cannot extrapolate what the result will be, because you may get people switching votes on a tactical basis on the view that 'I hate that party', so I'll not vote for my own party, I'll vote for somebody else," said Hayward in an interview with CNBC. "And that's what I think will happen in a lot of constituencies, even if we don't have formal alliances between political parties." "It's very hard to read the political tea leaves," Tom Brake, Liberal Democrats' spokesperson on Brexit, acknowledged in an interview with CNBC earlier this week. Brake's party has been strongly in favor of a second referendum on EU membership, and would campaign for the U.K. to remain inside the world's largest trading bloc. This stance helped attract new voters in European parliamentary elections earlier this year, and his party is currently polling at 18% as of Tuesday, according to Politico's poll of polls. Johnson's Conservatives, meanwhile, lost support in that same European election to the single-issue Brexit Party, and currently has support from 34% of potential voters in national polls. If the U.K. has not left the EU before the next national election, many expect those numbers will not reach the necessary level for the party to win a clear majority of seats in the House of Commons, despite Johnson's widely praised skills as a campaigner. "If he doesn't manage to get the Brexit Party on board, perhaps get them to stand down in that election, then he has a difficulty," said Brake. "That ends up splitting the Brexit vote between the Conservatives and the Brexit Party."