(CNN)Approve my deal or risk no Brexit at all, British Prime Minister Theresa May will warn lawmakers Monday as she tries to shore up support ahead of a key vote Tuesday.
In a speech to workers at a factory in Stoke-on-Trent, a heavily pro-Brexit part of the UK, May will argue that Parliament has a duty to implement the result of the 2016 referendum in favor of leaving the European Union.
"If a majority had backed remain, the UK would have continued as an EU member state," she will say.
"No doubt the disagreements would have continued too, but the vast majority of people would have had no truck with an argument that we should leave the EU in spite of a vote to remain or that we should return to the question in another referendum."
Despite her forceful words, May is likely facing a defeat -- her bill is unpopular with both pro and anti-Brexit MPs. She previously postponed the vote, to the outrage of many in Parliament, when it looked sure to be defeated.
Since then, Parliament has been eager to assert its constitutional dominance. Last week, MPs voted in favor of preventing the UK from exiting the EU without any deal. They also gave May just three days to come up with an alternative plan if she is defeated on Tuesday.
Ugly debate
Hardline supporters of leaving the EU have expressed anger at signs Brexit may be slipping away, or that a second referendum might be held.
At regular protests outside Parliament, where pro and anti-Brexit demonstrators have been a regular sight for months, far-right groups have targeted MPs and journalists -- particularly those members of May's Conservative Party who are skeptical of Brexit or support holding another referendum.
In a letter to London's Metropolitan Police, MPs warned that "an ugly element of individuals with strong far right and extreme right connections ... have increasingly engaged in intimidatory and potentially criminal acts" against politicians, journalists, activists and the public.
According to her prepared remarks, May will use her speech on Monday to warn that a defeat of her Brexit deal in Parliament could degrade the debate even further and lead to widespread disillusionment among voters.
"I ask MPs to consider the consequences of their actions on the faith of the British people in our democracy," she will say.
"What if we found ourselves in a situation where Parliament tried to take the UK out of the EU in opposition to a remain vote?"
The Prime Minister will attempt to link any defeat of the bill to anti-Brexit MPs, saying "there are some in Westminster who would wish to delay or even stop Brexit and who will use every device available to them to do so."
"People's faith in the democratic process and their politicians would suffer catastrophic harm," she will say. "We all have a duty to implement the result of the referendum."
However, despite her targeting of Remainers, May's biggest challenge is still likely to come from hardline pro-Brexit lawmakers within her own party. Their opposition to what they see as an overly soft exit has dogged her deal from the start.