MPs have rejected Theresa May's Brexit deal with 432 voting against the motion.
It comes after more than two years of talks with the EU and months of parliamentary and intra-party wrangling on both sides of the Commons.
- Watch live: ITV News special programme on the historic Brexit vote in the House of Commons
From effigies of the prime minister and former cabinet members to a mock Titanic iceberg steered by Mrs May, remain and leave campaigners have been boisterously protesting outside the House of Commons in Westminster.
Here is how the day has unfolded so far:
0930: Cabinet met for its regular Tuesday morning briefing.
It was all smiles as Amber Rudd, Matt Hancock and Brexit Secretary Stephen Barclay arrived at Downing Street.
Immigration Minister Caroline Nokes caught attention arriving at the meeting wearing a bright pink hat - perhaps an attempt to bring some light relief to what is a tough day.
1300: Commons Speaker John Bercow confirmed to the House that four amendments would be put to MPs before the final vote on Theresa May's EU Withdrawal Agreement.
1830: Theresa May closed the debate with a speech from the Despatch Box.
Addressing the Commons, Mrs May said: "Our deal delivers certainty for businesses with a time-limited implementation period to prepare for the new arrangements of the future relationship. No deal means no implementation period.
"Our deal protects the rights of EU citizens living in the UK and UK citizens living in the EU so they can carry on their lives as before. No deal means no reciprocal agreement to protects those citizens' rights," she added.
Speaker John Bercow revealed one amendment to the deal was put to the House beforehand, but it was overwhelmingly defeated with 600 votes against.
The amendment, tabled by Tory MP John Baron, sought to give the UK the right to terminate the Irish border backstop without the agreement of the EU.
1930: MPs have rejected Theresa May's Brexit deal by 432 votes to 202, majority 230.