Jeremy Corbyn has said that Labour will back a December election. This means that it is now highly likely to happen. Indeed, the only thing that could prevent it would be if an amendment was added to the bill changing the franchise: for example, giving 16 and 17-year-olds or EU nationals the vote. In those circumstances, the government would likely not proceed with the bill.
Labour’s change in stance from last night’s vote, when it whipped its MPs to abstain on the motion under the Fixed-term Parliaments Act, looks like it has been driven by the SNP’s willingness to back the government on a pre-Christmas election.
If you add the SNP’s 35 MPs to the 299 votes the government got last night, you have a majority. This suggested that the government’s bill was likely to pass and it would have been a bad look for Labour to go into an election having fought to stop voters from having their say.