Donald Trump gave Theresa May a Brexit headache on Monday evening, describing the agreement reached between London and Brussels as "great for the EU."
The US President also warned the government's proposed deal with the EU could prevent a future trade deal between the UK and US.
Trump's comments came as the Prime Minister was attempting to woo more than 100 business leaders at a Downing Street reception as she tried to drum up support for her Brexit deal.
It has been revealed Parliament would vote on the agreement on December 11 – giving the PM just two weeks to convince doubters to back her controversial plan.
The size of her task was laid bare in the Commons on Monday afternoon where May underwent yet another gruelling session at the despatch box as Conservative MPs tore into the Brexit deal.
An attempt to win Labour support seemed to fall flat when a special briefing for opposition MPs, chaired by de facto Tory prime minister David Lidington, attracted fewer than 30 opposition MPs.
Speaking in the Commons in what was her third statement on the negotiations in less than a fortnight, May tried to win over MPs who are unhappy with the backstop plan which, if triggered, would see the UK remain in the EU customs union until a trade deal is implemented.
She said: "I do not pretend that either we or the EU are entirely happy with these arrangements. And that’s how it must be – were either party entirely happy, that party would have no incentive to move on to the future relationship.
May added: "Put simply, there is no deal that comes without a backstop, and without a backstop there is no deal."
Many Tory MPs seemed unmoved by her comments, with former foreign secretary Boris Johnson accusing cabinet ministers of promising businesses the UK would remain in the customs union and single market, while the Prime Minister was claiming the country would be able to strike free trade deals after Brexit.
"They can't both be right, which is it?" Johnson asked.
The business community has been a priority target for the government, with May and chancellor Philip Hammond hosting a briefing for City chiefs immediately after the Budget, at which the PM urged the assembled executives to publicly back her deal.
More recently, Hammond and business secretary Greg Clark tried to reassure dozens of leading chief executives on a conference call following the unveiling of May's Brexit deal earlier this month.
It was revealed last week that Downing Street sent a pro-Brexit deal presentation to all FTSE-100 companies in a further attempt to get leading business figures onside.
Iain Anderson, chair of communications firm Cicero, was one of those invited to the Downing Street Brexit briefing on Monday evening. He told City A.M.: "There is a huge amount of support for the Prime Minister from the business community for having negotiated a pragmatic deal and a vital economic transition for the U.K. and for Europe."
With the showdown vote now just 14 days away, Brexiters are bracing themselves for another bout of the so-called ‘Project Fear’ campaign, with the Treasury and Bank of England set to unveil their latest Brexit scenario economic forecasts this week.
One leading Brexiter told City A.M. "Between now and the Parliamentary vote you can expect to see a condensed Remain v Leave campaign fought all over again, with May's deal taking the place of the Remain option and all the usual suspects pushing Project Fear Part 2 about a no-deal exit."