"That wouldn't be a good thing".
Prime Minister Theresa May is struggling to overcome opposition within her Conservative Party to the agreement she stuck with Brussels, raising concerns about a no-deal Brexit among businesses and investors.
Speaking to The Sun, Theresa May said she would also be "going around the country" over the coming days in order to win support for the agreement that was accepted by European Union leaders over the weekend.
May's spokesman said there had already been positive and productive discussions on an ambitious trade deal through joint working groups and cited public consultations on both sides of the Atlantic as signs of progress.
"We have a working group set up and that is working very well, has met several times and is continuing to work with the USA on this".
The UK is scheduled to leave the European Union on March 29, 2019, with a 21-month transition period kicking off when all rules will remain unchanged and during which time the Political Declaration will be worked on in finer details to hammer out of free trade agreement between Britain and the European Union for the future.
The British government has fought to stop the ECJ from hearing the case, saying it is hypothetical and irrelevant because ministers have no intention of reversing Brexit.
There was no formal vote required by the remaining 27 members of the European Union meeting on Sunday, as the withdrawal agreement was approved by consensus.
Fernando Alonso and NASCAR racer Jimmie Johnson seat swap
Thankfully, though, there has been no sight of those ubiquitous Alonso facemasks. I'm shier than people think and I want it go by quickly.
Under the plans, to be set out in full this week, a motion on the deal will be put before parliament where MPs will have the opportunity to amend it before deciding whether to accept or reject the deal.
Trump's comments are also potentially inflammatory as they align him publicly with pro-Brexit campaigners such as Boris Johnson, the former foreign secretary, who are trying to force May to ditch her deal.
When May defended the deal in parliament on Monday, more than an hour passed before a Conservative voiced support for the agreement. "It would open the door to more division and more uncertainty, with all the risks that will entail".
Michelle O'Neill, Sinn Fein's leader in Northern Ireland, also said May's deal is "the least worst outcome" and preferable to a no-deal Brexit.
The deal includes a temporary, last-resort backstop with slightly different provisions for Northern Ireland from the rest of the United Kingdom.
Her spokesman declined to confirm or deny reports that Number 10 is considering a possible TV debate with Mr Corbyn, something the Labour leader has made clear he would relish.
The European Court of Justice is assessing the issue under an accelerated procedure, since Britain is due to leave the bloc on March 29. "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".
Much of the focus of the deal has been on goods, rather than on financial services, Javed added, and details concerning trade and securities must still be ironed out.