Boris Johnson is calling on MPs to back his plan to hold an early general election on 15 October.
The PM has laid a motion in the Commons to secure the poll. To succeed, it needs the support of two-thirds of MPs.
But Labour, the SNP and the Liberal Democrats have said they will not vote in favour.
It comes after MPs backed a bill to block a no-deal Brexit if the PM hasn't agreed a plan with the EU ahead of the 31 October deadline.
Mr Johnson dubbed it a "surrender bill" that would "cut his legs off" for negotiations on a new deal, minus the controversial backstop.
But the bill passed all its stages in the Commons in one day, with the support of most opposition parties and Tory rebels, as they tried to push it through ahead of Parliament being suspended next week.
It will now go to the Lords for approval.