Throughout hours of televised debate, lawmakers set out competing visions of the country at this pivotal moment; whether it should keep close to the environmental and employment protections guaranteed by the E.U., or go down a path of deregulation and free trade made possible by Johnson's hardline Brexit deal.
Outside the House of Commons tens of thousands of anti-Brexit protesters marched through the streets of central London.
Many polls suggest that public opinion on Brexit may have flipped, with a narrow majority now favoring staying inside the E.U.
Brexit has seen politicians resort to increasingly violent language when describing their opponents, leading police to warn them not to inflame what has become a febrile atmosphere in the country.
Many members of Parliament — mostly women — have received death threats referencing their views on Europe.
One female lawmaker was murdered in 2016 and another was the subject of a foiled far-right plot to kill her.
On Saturday prominent opposition Labour Party lawmaker Diane Abbott was forced to have a police escort as she left Parliament, with at least one person seen verbally accosting her. Jacob Rees-Mogg, a key Johnson ally and vocal Brexit advocate, was also guarded by law enforcement as a pro-E.U. crowd chanted "shame on you."
These fierce divisions show no signs of abating, and the fate of Brexit itself remains uncertain.
Saturday's delay means the door is still open for a host of other options beyond Johnson's deal, including an early general election or even a second referendum.
The prime minister's plan seeks to scrap all of the major trading rules that currently bind the U.K. to the E.U. But it will keep some of these ties in Northern Ireland.
This is an attempt to avoid a "hard border" being created with the Irish Republic, which is a separate country and will remain part of the E.U. after Brexit.