The UK is on course for a December general election after Labour announced its conditions to back the move had been met.
Jeremy Corbyn has pledged to launch an "ambitious and radical" election campaign after assurances that a no-deal Brexit was "off the table".
His party abstained from a vote last night on whether to hold a pre-Christmas election, and the Prime Minister failed to secure the two-thirds majority required to press ahead.
But Boris Johnson is set to table another motion for a December 12 poll today.
The short Bill sets aside the Fixed-Term Parliaments Act, requiring only a simple majority of MPs to support it.
This morning, Mr Corbyn told his shadow cabinet: "I have consistently said that we are ready for an election and our support is subject to a no-deal Brexit being off the table.
"We have now heard from the EU that the extension of Article 50 to January 31 has been confirmed, so for the next three months, our condition of taking no-deal off the table has now been met."
However, the Liberal Democrats and the SNP are reluctant to accept the proposed election date, fearing it allows time to bring the Withdrawal Agreement Bill before MPs ahead of the start of the campaign.
They have previously signalled support for a poll on December 9, but could put forward a proposal for an election on December 11, which a Number 10 source said the government "could accept".