Theresa May has warned opponents of her Brexit deal that they risk “letting the British people down” as Labour said the prime minister faced a “humiliating defeat” in Tuesday’s crunch vote.
She urged critics to give the deal “a second look”, insisting new assurances on the Irish border had “legal force”.
She said the “history books” would judge if MPs delivered on Brexit while safeguarding the economy and security.
But Jeremy Corbyn said the PM had “completely and utterly failed”.
And the SNP said the PM was “in fantasy land and the government should stop threatening no-deal”.
MPs will vote on the terms of the UK’s withdrawal from the EU and declaration on future relations on Tuesday evening.
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.
Assistant whip Gareth Johnson has become 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.”
Letter from Attorney General Geoffrey Cox to Prime Minister about the Tusk/Junker letter pic.twitter.com/6Uab6VDUOi
— John Stevens (@johnestevens) January 14, 2019
Ahead of the vote, Mrs May has been briefing MPs on the controversial issue of the “backstop” – the fallback plan to avoid any return to physical Northern Ireland border checks.
She said she had won new written assurances from the EU that the contingency customs arrangement being proposed would be temporary and, if it was ever triggered, would last for “the shortest possible period”.
A “no-deal” Brexit is where the UK would cut all ties with the European Union overnight.
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.
Her “absolute conviction” was that the two sides would be able to finalise their future relationship by the end of 2020, meaning the backstop would never be needed.
While the UK would “never countenance” introducing a hard border, she said the EU had made it clear that in the event of the UK leaving without a deal, a raft of checks would be introduced “in full” – “changing everyday life” for people in Northern Ireland.
“I say to members on all sides of this house, whatever you may have previously concluded, over these next 24 hours, give this deal a second look,” she said.
“It is not perfect but when the history books are written, people will look at the decision of this House tomorrow and ask ‘did we deliver on the country’s vote to leave the EU, did we safeguard our economy, security or union or did we let the British people down’.”
Mrs May’s last-ditch efforts come amid reports MPs plan to take control of Brexit if her deal is defeated.
Former Labour leader Ed Miliband said the PM must make the government “the servant of the House” if the deal was rejected, giving Parliament an “open and honest process” to express their will.
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.