MPs have backed a bill to block a no-deal Brexit, which could trigger Boris Johnson to seek a general election.
Opposition MPs and Tory rebels ensured the bill passed its first stage by 329 votes to 300.
If it is passed in full, it will force the PM to ask for an extension beyond the 31 October Brexit deadline if a deal has not been agreed with the EU.
But Mr Johnson has warned he would push for an immediate vote on an early general election if it went through.
This vote was on the second reading – the parliamentary stage which examines the main principles of the bill – and was the first chance for MPs to show whether they supported the bill.
MPs are now voting on amendments to the bill – put forward by MPs, but chosen by the Deputy Speaker.