(Bloomberg) –The Brexit impasse looks set to continue after the main opposition Labour Party made clear it won’t back Boris Johnson’s bid for an early election, with the prime minister accusing Parliament of holding the country “hostage” by not allowing the vote.

Labour’s refusal to support Johnson’s motion for a snap poll on Dec. 12 means the prime minister is almost certain to fall short of the two-thirds majority in the House of Commons vote on Monday. The European Union has said it will announce by Tuesday the terms of any Brexit delay, likely thwarting Johnson’s pledge to leave the trading bloc on Oct. 31 with or without an exit deal.

The government reiterated it would keep pushing for an election if it loses the vote, and a U.K. official said the government would also look at “all options” if Labour blocks the motion as expected on Monday. Earlier, ministers rejected a plan put forward by the pro-EU Liberal Democrats and Scottish National Party to secure an election via a law requiring only a simple majority in Parliament — but which crucially could then be amended by MPs.

Conservative Party Chairman James Cleverly called it a “gimmick” that the opposition could use to thwart Brexit altogether by stopping Parliament from debating the divorce deal Johnson reached with the EU.

“They have obviously made it clear that they have no intention of wanting Brexit to be done, no intention of wanting the Withdrawal Bill,” Culture Secretary Nicky Morgan told Sky News on Sunday. “It is important for the sake of the country that we bring this uncertainty to an end.”

Read: Sultanate’s crude oil production crosses 29mn barrels in Sept

Both the Liberal Democrats and SNP stand to gain from an election conducted before Brexit is delivered, while their plan to bring forward the poll date to Dec. 9 increases the chances that students — considered to be among the most pro-EU voters — will still be at their universities to cast ballots.

Liberal Democrat MP Chuka Umunna said the party made the move because it had become “highly unlikely” that the current Parliament would vote for holding a second referendum on leaving the trading bloc. The party has pledged to block Brexit if elected, though they currently hold just 19 seats in the House of Commons.

While the route to an election via a simple majority likely has some appeal to the government, the risk lies in any amendments MPs seek to attach to the law. Liberal Democrats leader Jo Swinson tried to assuage those concerns, telling the BBC the party realized “time pressure” meant it couldn’t pursue its other goals — including lowering the voting age from 18 — via its proposed bill.

Labour, which has been criticized by some of its MPs for not matching the Liberal Democrats’ full-throated opposition to Brexit, ruled out backing the election proposal, calling it “entirely ridiculous.”

“It would need cross-party support to get through the House of Commons procedures and then it would be subject to all kinds of amendments,” Labour’s health spokesman Jon Ashworth told Sky News on Sunday. “It’s just a stunt so the Lib Dems can get on the telly today.”

But Ashworth declined to say whether Labour would back an early election if the EU agrees to a Brexit extension to Jan. 31 as Johnson had been forced by Parliament to request.

“If they give us that extension until January, then we will have to consider it, but at the moment we don’t have that clarification,” Ashworth said. “We cannot support Boris Johnson’s plans until we’ve got an absolute reassurance that no-deal is off the table.”

Catch-22

That stance effectively creates a Catch-22 for Monday’s vote, with Labour refusing to back a snap poll until it’s heard from the EU, and the trading bloc waiting to see what happens in Parliament before announcing its decision on pushing back the Brexit deadline. Finnish Prime Minister Antti Rinne said Sunday he’d be very surprised if the EU didn’t agree to extend to the deadline until Jan. 31.

The apparent schism among opposition parties — with the Liberal Democrats and SNP diverging from Labour on the best strategy to bring down Johnson’s Tories — further complicates matters.

Meanwhile Arlene Foster, leader of the Democratic Unionist Party that props up the U.K. government, told the Financial Times the party’s 10 MPs in Westminster would vote against Johnson’s election request because he had linked it to getting his Brexit legislation through the House of Commons.

“We need to amend that legislation and we need time to do that,” Foster said. The DUP will continue to oppose the Brexit deal because it will bring in customs checks between Northern Ireland and Great Britain, she said.

Read: Trade Woes Push IMF Global Growth Outlook to Decade-Low of 3%

Neither Morgan nor Cleverly laid out the government’s plans if it loses on Monday, but Johnson’s office has previously said it would focus on its domestic agenda rather than trying again to ratify the divorce deal with Brussels. That would raise the risk of the U.K. crashing out of the trading bloc without a divorce deal, which risks creating economic turmoil and causing shortages of basic goods like food and medicine.

In comments released late Saturday, Johnson again tried to heap pressure on politicians to back a new vote to resolve the Brexit standoff. Parliament has “run its course,” he said.

“They must also agree to an election on Dec. 12,” Johnson said in a broadcast statement. “If they refuse this timetable — if they refuse to go the extra mile to complete Brexit — then I will have no choice but to conclude that they are not really sincere in their desire to get Brexit done.”

–With assistance from Kati Pohjanpalo.