The UK is now more likely to stay in the European Union than to leave without a deal, Theresa May will say in a speech.
Addressing workers at a factory in Stoke, where 69.4% of voters backed Leave, the prime minister will also say that if the referendum result is not honoured, people’s faith in politics will suffer “catastrophic harm”.
When the people are asked to decide something, their response carries a “profound significance”, she will add.
Speaking the day before MPs vote on her withdrawal agreement, the PM will claim that some in Westminster will use “every device available to them” to “delay or even stop Brexit”.
It was reported on Sunday that there is a backbench plot to wrest control of the legislative agenda away from Mrs May if her deal fails.
Were such a plan to succeed, the government would lose control of parliamentary business, threatening its ability to govern, putting Brexit legislation at risk.
Mrs May now believes, Downing Street said, that “based on the evidence of the last week”, MPs managing to block Brexit is more likely than the UK leaving the EU without a deal.
Speaking a few weeks after calling off a previous vote on her withdrawal agreement because she knew it would be rejected, Mrs May will ask MPs to consider various scenarios.
“Imagine,” she will say, “if an anti-devolution House of Commons had said to the people of Scotland or Wales that despite voting in favour of a devolved legislature, parliament knew better and would over-rule them. Or else force them to vote again.”
She will add: “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?
“People’s faith in the democratic process and their politicians would suffer catastrophic harm.”
She will also go back to the fundamentals of the referendum, observing that during the 2016 campaign, “both sides disagreed on many things, but on one thing they were united: what the British people decided, the politicians would implement”.
She will continue: “In the run-up to the vote, the government sent a leaflet to every household making the case for Remain. It stated very clearly: ‘This is your decision. The government will implement what you decide.’
“Those were the terms on which people cast their votes. If a majority had backed Remain, the UK would have continued as an EU member state.
“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.”
The prime minister will say that previous referendums have been honoured, commenting: “When the people of Wales voted by a margin of 0.3%, on a turnout of just over 50%, to endorse the creation of the Welsh Assembly, that result was accepted by both sides and the popular legitimacy of that institution has never seriously been questioned.
“Parliament understood this fact when it voted overwhelmingly to trigger Article 50. And both major parties did so too when they stood on election manifestos in 2017 that pledged to honour the result of the referendum.”
The prime minister will make this plea: “I ask MPs to consider the consequences of their actions on the faith of the British people in our democracy.
“On the rare occasions when parliament puts a question to the British people directly we have always understood that their response carries a profound significance.
“We all have a duty to implement the result of the referendum.”