An alliance of governing Conservative and opposition legislators has dealt May two defeats in as many days - symbolic setbacks that suggest a power shift from the executive to the legislature.
On Wednesday, Parliament voted for an amendment calling on the government to set out its Plan B within three working parliamentary days of the January 15 vote, rather than the 21 days specified in Brexit law.
So if May came back with an alternative plan, that could be amended by MPs, giving parliament far more scope in setting the direction.
Pro-EU Conservative politician Dominic Grieve, who proposed the measure, said it was meant to speed up decisions, to help avoid a no-deal Brexit and "the calamitous consequences that would follow on from it".
There was a major row in the Commons over whether the amendment could even be put to a vote, with Speaker John Bercow apparently disregarding the advice of his own clerks that it could not.
Late Tuesday, legislators backed an amendment to the Finance Bill that puts roadblocks in the way of government spending on no-deal Brexit measures.
Officially, May has not given up hope of winning the backing of the Commons for the divorce agreement she negotiated over 18 months of talks with the EU.
Winning over the Brexiteer side of the argument can be done if the European Union offers some legal assurances that the Northern Ireland backstop mechanism - seen as a trap to keep the United Kingdom tied to European Union rules by Brexiteers - will be temporary.
But he refused to say that the Government would rule out a no deal, saying: "The default is in law that unless we have a deal then we will fall into no deal".
Amid a series of furious points of order lasting more than an hour, a series of Conservatives argued that Commons precedent dictated that business motions could only be changed by ministers.
As the country counts down to Brexit while politicians remain deadlocked over how best to oversee its departure on March 29, Tesco said it had increased stockholdings of ambient foods such as bottles, packets and tins and made clear plans for each product category. And there is no clear majority in Parliament for any single alternate course.
"If the prime minister's Brexit deal is defeated next week, she must return to parliament as soon as possible and give MPs a real say on what happens next".
Nottinghamshire campaigners believe arguments over Brexit "could go on forever" if Theresa May's Brexit deal is approved by parliament next week.
"What we have is a deal with the European Union that we can accept and we can implement and that is what we should be doing".
"Our organisations remain committed to playing their part in managing Brexit in the best interests of farmers and the United Kingdom public in the years ahead, but we believe that leaving without a deal on March 29 will lead, very quickly, to the opposite outcome".
"Almost nothing of what was promised during the referendum campaign has been delivered and as such I will be voting against the Prime Minister's Deal next week".