Boris Johnson will urge MPs to “open a new chapter in our national story” by backing his post-Brexit trade deal with the EU in a Commons vote on Wednesday.
Parliament is being recalled to put the deal into law, a day before the UK severs ties with the European Union.
In a speech to MPs, the prime minister will say the deal – agreed on Christmas Eve – allows the UK to take “control of our laws and our national destiny”.
But he will also stress the UK intends to be the EU’s “best friend and ally”.
The deal hammered out with Brussels over nine tortuous months sets out a new business and security relationship between the UK and its biggest trading partner.
The EU (future relationship) Bill – which puts it into UK law – is expected to receive the backing of Parliament, thanks to Mr Johnson’s large Commons majority and the support of the opposition Labour Party.
Labour leader Sir Keir Starmer – who campaigned against Brexit – has said the “thin” agreement does not do enough to protect jobs, the environment and workers’ rights.
But – despite objections from leading members of his own party – he will order his MPs to vote for it, as the only alternative at this stage would be a no-deal exit, which he argues would be even more damaging to the UK economy.
All other opposition parties, including the SNP, the Lib Dems, Plaid Cymru and all Northern Ireland parties that take seats at Westminster, have indicated they will be voting against the deal.
But the prime minister received a boost from a powerful group of backbench Tory Brexiteers and serial rebels, who have indicated they will back the deal.
The European Research Group (ERG) said it had examined the text in detail and concluded that it “preserves the UK’s sovereignty as a matter of law”.
In a speech opening five hours of Commons debate, Mr Johnson is expected to say: “The central purpose of this bill is to accomplish something which the British people always knew in their hearts could be done, but which we were told was impossible – namely that we could trade and cooperate with our European neighbours on the closest terms of friendship and goodwill, whilst retaining sovereign control of our laws and our national destiny.”
He will claim the deal – which comes four and half years after Britain voted to leave the EU and a year after it officially left – had been reached in record time, when compared to other trade treaties.
“We have done this in less than a year, in the teeth of a pandemic, and we have pressed ahead with this task, resisting all calls for delay, precisely because creating certainty about our future provides the best chance of beating Covid and bouncing back even more strongly next year,” he is expected to tell MPs.
And he will stress that the UK intends to be “a friendly neighbour – the best friend and ally the EU could have – working hand-in-glove whenever our values and interests coincide while fulfilling the sovereign wish of the British people to live under their own laws, made by their own elected Parliament”.
“That is the historic resolution delivered by this bill,” he will add, calling it a “a new chapter in our national story” that will reassert Britain as “a liberal, outward-looking force for good”.
European Commission President Ursula von der Leyen and European Council President Charles Michel are due to sign the international treaty ratifying the deal on Wednesday morning in Brussels.
The document will then be flown across the Channel in an RAF plane for Mr Johnson to sign it in Downing Street, a No 10 spokesman said.
The European Parliament has begun its scrutiny of the agreement but will not get a chance to ratify it before the UK leaves the EU single market and customs union at midnight on Thursday.
The deal has, however, been given the unanimous backing of ambassadors from the 27 nations and the member states gave their written approval on Tuesday.
MPs are set to debate the bill for five hours, starting at 09:30 GMT, before a vote.
It will then move on to the Lords, which is also expected to back it, before receiving Royal Assent.
Labour has called on the government to provide help to British businesses facing upheaval in the new year, including “clear communications”, an acceleration in the recruitment of customs officials, forbearance for firms coming to terms with new rules, commitment to British supply chains and financial support for affected firms.
Shadow chancellor Anneliese Dodd’s said: “The fact that a catastrophic no-deal scenario has been avoided means that many businesses across the country are now breathing a sigh of relief.
“But the government’s irresponsible, eleventh-hour approach to the negotiations means there are many questions still unanswered with just days to go until the end of the transition period.”
The deal comes as the UK government announced it has signed a deal that will allow British businesses to continue trading with Turkey on the same terms after Brexit.
The tariff-free arrangements underpin a trading relationship which the UK government said was worth £18.6bn last year.
The UK has rolled over dozens of trade deals with countries around the world since deciding to leave the EU’s trading arrangements.
The vast majority of the 63 trade deals the UK has signed over the past two years have retained the same terms as before Brexit.