Prime Minister Theresa May has warned MPs that voting against her Brexit deal will take Britain “back to Square one”, according to a pre-written Commons speech to be delivered on Monday.
EU leaders approved the agreement on the UK’s withdrawal from the bloc on Sunday after 20 months of negotiations.
The deal still needs to be approved by the UK Parliament, which is expected to vote on the deal on December 12.
However, Labour, the Lib Dems, the SNP, the DUP and many Conservatives MPs are expected to vote against the plan.
May will deliver a statement on Brexit in the Commons at around 3.30pm, urging MPs to get behind her deal.
She will say MPs have a choice between backing the deal and ending the uncertainty surrounding Brexit or rejecting it and going back to the drawing table.
“We can back this deal, deliver on the vote of the referendum and move on to building a brighter future of opportunity and prosperity for all our people,” she will say.
“Or this house can choose to reject this deal and go back to Square one. It would open the door to more division and more uncertainty, with all the risks that will entail.”
Business leaders back May's deal
Business leaders have supported the deal, calling on MPs to do the same to avoid a no-deal Brexit scenario that would harm the UK economy.
TheCityUK, which represents banks and insurers in the Square Mile, said the focus must now be on securing the withdrawal agreement and the transition period, which is “critical for our industry and many others”.
“There is much still to be negotiated to define the future relationship. The sooner that can get started, the better,” said Miles Celic, the organisation’s boss.
The Institute of Directors (IoD) said they were also against an outcome that leaves Britain without a deal. The IoD’s director general Stephen Martin said the deal “provokes a wide range of reactions across the political spectrum, and indeed among business leaders, but the steer from our members is that avoiding no deal must be the main priority”.
Helen Dickinson, chief executive of the British Retail Consortium, said it was now up to parliament to ensure the UK has a transition period from 29 March when the UK leaves the EU and avoid a “chaotic no-deal Brexit” for consumers.
UK GDP to fall 4% on Brexit deal
The backing from business leaders came even as a report from the National Institute of Economic and Social Research (NIESR) said May’s deal would see the UK economy shrink by 3.9%, or £100bn annually, by 2030.
The NIESR said tax revenue would fall by 1.5% – 2%, the equivalent of £18bn-£23bn less to spend on public services at today’s prices.
“If the government’s proposed Brexit deal is implemented so that the UK leaves the EU customs union and single market in 2021, then by 2030 GDP will be around 4% lower than it would have been had the UK stayed in the EU,” the NIESR said.
“This is largely because higher impediments to services trade make it less attractive to sell services from the UK. This discourages investment in the UK and ultimately means that UK workers are less productive than they would have been if the UK had stayed in the EU.”
At a news conference in Brussels on Sunday after the EU leaders voted, May said her Brexit deal would end freedom of movement, protect the constitutional integrity of the UK and ensure a return to "laws being made in our country by democratically elected politicians interpreted and enforced by British courts".
Some MPs have opposed the deal because of a backstop, which aims to avoid a hard Irish border. The backstop would mean Northern Ireland would essentially remain in the EU if trade talks collapse and there’s no future deal.