Tory rebels and opposition MPs have cleared the first hurdle in their attempt to pass a law designed to prevent a no-deal Brexit.
Commons Speaker John Bercow granted them a debate and a vote on taking control of the Commons agenda.
If successful, they would be able to bring forward a bill seeking to delay the UK’s exit date beyond 31 October.
No 10 officials have warned the prime minister will push for an election if they succeed.
Earlier, Conservative MP Phillip Lee defected to the Liberal Democrats ahead of the Commons showdown.
His defection means Boris Johnson no longer has a working majority.