Opposition leaders have agreed not to support Boris Johnson’s demand for a general election before the EU summit on October 17.
The prime minister will ask MPs on Monday to vote to hold an election October 15.
Jeremy Corbyn spoke with the leaders of the main opposition parties on Friday to discuss their resistance to holding a vote before the prospect of a no-deal Brexit on October 31 is eliminated.
Labour, the Liberal Democrats, the SNPs and Plaid Cymru are all understood to be planning on voting against or abstaining from the Fixed-Term Parliament Act when it returns to the Commons on Monday.
Opposition leaders including the Lib Dems’ Jo Swinson, the SNP’s Ian Blackford and Plaid Cymru’s Liz Saville Roberts discussed tactics on Friday morning as Johnson returned to the campaign trail of the election he is yet to successfully trigger.
Any extension to Article 50 would need to be signed off by EU leaders at the upcoming summit.
Johnson has said he would “die in a ditch” before asking Brussels for another delay.
But the government may have no choice as parliament is due to soon pass a law that will require the PM to request at extension.
The decision by the opposition parties, agreed during a conference call on Friday morning, means an election is now more likely to take place in November.
Labour said the leaders discussed efforts to prevent a “damaging” no-deal Brexit and to hold an election “once that is secured”.
A Lib Dem spokeswoman said the parties “will all vote against or abstain on Monday”.
The development came a day after the PM suffered a torrid day in which his brother resigned from government while describing being torn between family and “the national interest”.