Theresa May has urged MPs to back her Brexit deal “for the country’s sake” as Tuesday’s Commons vote looms closer.
She warned of “paralysis in Parliament” if the deal is rejected and said trust in politics would suffer “catastrophic harm” if the UK did not leave the EU.
The PM welcomed new EU assurances over the impact of the deal on Northern Ireland, saying they had “legal force”.
The EU said it didn’t want to use the “backstop” but, if it did, it would be for “the shortest possible period”.
The “backstop” is the fallback plan to avoid any return to physical Northern Ireland border checks.
In a letter to Mrs May, the EU said commitments to look at alternatives to the customs arrangement and to fast-track talks on future relations had “legal value” and would be treated “in the most solemn manner”
Speaking in Stoke, Mrs May said “they make absolutely clear that the backstop is not a threat nor a trap”.
Attorney General Geoffrey Cox said the assurances offered “legal force” to the UK, but admitted they did not alter the “fundamental meanings” in the Withdrawal Agreement – namely that the UK is indefinitely committed to the backstop if it comes into force, as neither side can unilaterally withdraw from it.
Critics said they fell way short of the firm end date or the unilateral right to withdraw they wanted, with the Democratic Unionist Party saying “nothing has changed” and accusing the prime minister of “foolish talk”.
Assistant whip Gareth Johnson became the latest member of the government to quit his job over the deal, saying in his resignation letter to the PM that it would be “detrimental to our nation’s interests”.
He added: “The time has come to place my loyalty to my country above my loyalty to the government.”
Mrs May’s speech comes amid reports MPs plan to take control of Brexit if her deal is defeated.
Labour and the other opposition parties will vote against the deal while about 100 Conservative MPs, and the Democratic Unionist Party’s 10 MPs, could also join them.
The letter from Presidents Juncker and Tusk was deliberately released at the moment No 10 hoped it might have the most impact – the eve of the crucial Brexit vote.
But regardless of the timing, the attempt to reassure hasn’t done enough to convince many senior Brexiteers to swing behind the prime minister’s deal.
The contentious Northern Ireland backstop remains the biggest sticking point, and nothing short of a legally watertight guarantee that it can’t go on indefinitely will be enough for many of those with concerns.
At this stage, the EU has made clear it won’t reopen the negotiated Withdrawal Agreement to include such a guarantee.
So, however warm the words of reassurance offered today, it seems they won’t be enough to persuade many opponents to Mrs May’s deal to change their mind.
Speaking to factory workers, Mrs May said she now believed MPs blocking Brexit was more likely than a no-deal scenario.
“As we have seen over the last few weeks, 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…
“While no deal remains a serious risk, having observed events over the last seven days, it is now my judgment that the more likely outcome is a paralysis in Parliament that risks there being no Brexit.”
A “no-deal” Brexit is where the UK would cut ties with the European Union overnight without a transition period.
Theresa May’s government, and many others, believe this would be hugely damaging and want a more gradual withdrawal. But if Parliament can’t agree on that, and nothing else takes its place, the UK will leave without a deal.
This would mean the UK would not have to obey EU rules. Instead, it would need to follow World Trade Organization terms on trade. Many businesses would see new taxes on imports, exports and services, which are likely to increase their operating costs. That means the prices of some goods in UK shops could go up.
The UK would also lose the trade agreements it had with other countries as a member of the EU, all of which would need to be renegotiated alongside the new agreement with the EU itself.
Manufacturers in the UK expect to face delays in components coming across the border.
The UK would be free to set its own immigration controls. However some UK professionals working in the EU and UK expats could face uncertainty until their status was clarified. The European Commission has said that even in a no-deal scenario, UK travellers won’t need a visa for short visits of up to 90 days.
The border between Northern Ireland and the Irish republic would become an external frontier for the EU with customs and immigration controls, though how and where any checks would be made is not clear.
Some Leave supporters think that leaving without a deal would be positive if the right preparations were made. They say criticism is scaremongering and any short term pain would be for long term gain.
But critics – including both Brexit supporters and opponents – say that leaving without a deal would be a disaster for the UK: driving up food prices, leading to shortages of goods and gridlock on some roads in the South East resulting from extra border checks.
