The Sunday afternoon session at Chequers, the prime minister's country residence, is expected to include prominent Brexit advocates including former foreign secretary Boris Johnson and Jacob Rees-Mogg.
According to Reuters, the United Kingdom lawmakers should now vote on a range of Brexit options on Wednesday, giving parliament a chance to indicate whether it can agree on a deal with closer ties to Brussels, and then try to push the government in that direction.
In fact, incensed by comments from May on Wednesday night that pinned the blame for the Brexit chaos on them, many British lawmakers have now hardened their resistance to the deal she is due to bring back before them next week.
The "People's Vote March" snaked from Park Lane and other locations to converge on the British Parliament, where the fate of Brexit will be decided in the coming weeks.
If the deal is not approved, Britain has until April 12 to come up with a new plan, such as leaving without a deal or cancelling Brexit.
Theresa May insisted tonight it was the "moment of decision" for MPs as she accepted European Union terms for delaying Brexit by at least two weeks.
Jet Airways chairman steps down as banks move in with rescue plan
The SBI-led consortium of lenders is working on a resolution plan for the cash-strapped Jet Airways for the last five months. Jet Airways, which is facing a severe cash crunch, defaulted on a domestic loan repayment in December.
In a letter to all MPs on Friday evening, Mrs May said: "If it appears that there is not sufficient support to bring the deal back next week, or the House (of Commons) rejects it again, we can ask for another extension before 12 April - but that will involve holding European Parliament elections".
A massive crowd of over one million marched through central London on Saturday to demand that MPs grant them a fresh referendum on Brexit. The government, which usually controls the scheduling of votes in Parliament, said the lawmakers' move "upends the balance between our democratic institutions and sets a unsafe, unpredictable precedent for the future".
May's deal was defeated in parliament by 149 votes on March 12 and by 230 votes on January 15, but she had signaled that she would bring it back a third time this week.
Just last week, Brussels agreed to postpone Brexit as fears of a chaotic "no-deal" scenario continue to grow. But if Parliament doesn't approve a deal by the end of next week, the deadline is April 12.
Several reports surfaced in British media over top ruling party members urging PM Theresa May to resign over her weakened political position and inability to get support on the procured deal.
Among the 27 remaining European Union states, France has the most hardline stance, while Germany and the Netherlands are ready to give Britain more time to break the impasse.
Parliament may take a series of votes this week to determine what proposals, if any, could receive majority support.