Theresa May has been warned by a leading German politician that she is "delusional" if she believes she can get a good trade deal from Donald Trump.
A senior member of Chancellor Angela Merkel's Social Democrat coalition partner, Axel Schafer said the PM's hope that President-elect Trump will look favourably on the UK will come to nothing.
Referring to the shock election of Mr Trump, Mr Schafer told The Times: "What changed is the likelihood of a speedy and preferential trade deal between UK and US.
"Even before Tuesday the chances were rather low, now the hope for this kind of deal seems delusional."
The pointed remarks came after ministers talked-up the chances of a close working relationship with the surprise winner of the race to the White House.
Underlining the starkly different approach to Mr Trump taken by London and the continent, Foreign Secretary Boris Johnson told his EU counterparts to end the "whinge-o-rama" over the outcome of the US election.
The comments came as Liberal Democrat leader Tim Farron said his party would vote against triggering Article 50 which formally launches withdrawal negotiations with the EU, unless there was a guarantee that the final Brexit deal with Brussels is put to a fresh referendum.
He insisted he respected the decision made by voters in favour of leaving the EU but said nobody should have a deal "imposed" upon them.
Although the Lib Dems only have eight MPs they have more than 100 peers in the Lords, which could spell trouble for the Government if judges rule that a full Act of Parliament is required before Article 50 can be triggered, as the legislation would have to clear both Houses.
Mr Farron said he believed the Lords would not get a vote either for or against Article 50 but would be able to move amendments.
The Lib Dem leader said: "We have said we will vote against Article 50 if our red line is not met, and it is a single, simple red line which is that we want to respect the will of the people and that means that they must have their say in a referendum on the terms of the deal.
"It is the only logical and it is the only democratic option on the table. There will be a referendum at the end of this process so that nobody would have imposed upon them something they didn't vote for."
He told the BBC: "We believe that what started with democracy last June - which we totally respect - must not now end up with a stitch-up, with a deal being imposed on the British people that absolutely nobody voted for."
MPs from other parties - including a Labour frontbencher - have indicated they would be prepared to oppose Article 50.
The Government is challenging a High Court ruling that Parliament must have the final say on triggering Article 50 with a hearing in the Supreme Court next month, arguing that prerogative powers could be used to trigger Article 50.
An outline of the grounds for appeal published by the Brexit Department said the High Court was mistaken and should have accepted "the Crown retains the power to give effect to the result of the EU referendum" by taking the "first step in the process" by notifying that it is triggering Article 50.
The Government's lawyers will argue that "in any event, the continued existence of the power to take that first step is clearly established and authorised by Parliament".
However, the Guardian reports that Government lawyers are looking at deploying new tactics when they try to persuade the Supreme Court to overturn the High Court ruling.
The legal team could argue that Parliament can reverse the Article 50 decision at any point, meaning its sovereignty has not been infringed, and Mrs May can trigger the process herself, the newspaper has suggested.
Prof Takis Tridimas, an expert in EU law at King's College London, told the newspaper: "I know that the issue of revocation is a live issue in terms of the supreme court hearing."
A Government spokeswoman said: "Our position is clear: the country voted to leave the EU and we will respect the will of the British people.
"The Government told the High Court that as a matter of firm policy, once given, the Article 50 notice would not be withdrawn. Because legal proceedings are under way it would not be appropriate to comment further."
Meanwhile, Britain could seek associate membership of the North American Free Trade Area, according to the Daily Telegraph.