More than three years since the United Kingdom voted 52 percent to 48 percent to be the first sovereign country to leave the EU, Mr Johnson will try to win parliament's approval for the divorce treaty he struck in Brussels on Friday. The party has accused Johnson of selling out Northern Ireland, with deputy party leader Sammy Wilson calling it "toxic".
"Today we MPs have the chance to free you from the never-ending Brexit saga and move this country forward", he wrote in The Sun newspaper.
'A hard, divisive and - yes - painful chapter in our history would be at an end'.
"In the end and we have done all the preparatory work to ensure Australia is as best placed for any scenario in relation to Brexit", Senator Birmingham said heading into the Liberal Party's Federal Council meeting in Canberra on Saturday.
The European Parliament also has to approve the deal, but it unlikely to be voted down there. The proposal would withhold support for Prime Minister Johnson's Brexit deal until formal ratification legislation has passed.
If the amendment is approved by parliament, Johnson's deal would not then be put to a vote today.
Johnson returned overnight from the European Union summit in Brussels where he sealed the divorce deal and began a busy day of meetings and phone calls as he attempted to persuade lawmakers to ratify the pact at a rare sitting of Parliament.
The People's Vote Campaign seems to agree.
If he does seek an extension, European Union leaders would expect him to provide a justification for delay, and it is expected Johnson will say the delay is needed because Britain needs a national election to bring in a new Parliament to break the logjam. He has said he would rather "die in a ditch" than do so. These so-called amendments need to be approved by a vote in parliament, which would take place before a vote on approving the final text of the motion.
He insists that Brexit must happen this month to end to uncertainty that has weighed on the economy and dominated political and public debate.
However, the vote rests on a knife-edge.
The Democratic Unionist Party said it could not support the deal.
Opposition leader Jeremy Corbyn responded by imploring MPs to reject the deal, saying it is worse than former Prime Minister Theresa May's deal and Johnson's government can't be trusted.
"Boris Johnson's sell-out deal risks triggering a race to the bottom on rights and protections: putting food safety at risk, cutting environmental standards and workers' rights, and opening up our NHS (National Health Service) to a takeover by U.S. corporations", said Corbyn.
Some of the Tory rebels are supporting an amendment on Saturday asking MPs to back the deal only on condition that it is ratified before Britain leaves the EU.
The Daily Express front page said: "Respect the will of the people and let's move on".