British Prime Minister Theresa May's Brexit strategy came under fresh scrutiny Tuesday following reports of a disastrous meeting with European Commission chief Jean-Claude Juncker.
May has dismissed as "Brussels gossip" accounts of tension at last week's Downing Street dinner, but faces accusations of botching the first face-to-face talks with EU leaders since triggering Brexit.
The report came just days after German Chancellor Angela Merkel warned Britain that it should have no "illusions" that it could continue enjoying the benefits of EU membership while outside the bloc.
May responded by accusing the other 27 EU countries of lining up against Britain, in a sign of hardening positions on both sides.
Formal negotiations will not begin until after Britain's election on June 8, in which May is expecting to return to office with an increased parliamentary majority.
"As we have seen in recent days, it will not be easy," May wrote Tuesday in a regional newspaper.
"Across the table from us sit 27 European member states who are united in their determination to do a deal that works for them.
"We need that same unity of purpose here at home to ensure we can get a deal that works in Britain's national interest too."
EU leaders unanimously backed a tough Brexit strategy at a summit on Saturday, their first since May triggered the Brexit process on March 29, starting a two-year countdown to leaving.
By contrast Britain's opposition parties have seized on the leaks to accuse May of "reckless handling" of the negotiations, and of having "no clue".
The European Parliament's chief negotiator, Guy Verhofstadt, said it was "time to get real" in a mocking tweet that twisted May's election promise that she offers "strong and stable leadership".
"Any Brexit deal requires a strong & stable understanding of the complex issues involved. The clock is ticking -- it's time to get rea
- 'Warning to the UK' -
Juncker gave an indication of the tensions at Wednesday's dinner when he warned afterwards that some in Britain "underestimate the technical difficulties we have to face".
But he said the meeting was "constructive", the same word used by May's office.
A report in Sunday's edition of the Frankfurter Allgemeine newspaper, however, said Juncker left the meeting "ten times more sceptical" about the prospect of a Brexit deal.
It said sources close to the negotiations put the chances of Brexit negotiations collapsing without a deal at more than 50 percent.
The two leaders reportedly clashed over May's insistence that talks on a new trade deal should start immediately, and that Britain has no obligation to pay the EU any money.
Brussels says the issue of Britain's outstanding bills -- estimated at up to 60 billion euros ($77 billion) -- must be settled before any talks on trade.
Juncker reportedly informed Merkel of his doubts, saying that May was in a "different galaxy" -- prompting her outspoken comments the following day.
Holger Schmieding, chief economist at Berenberg Bank, the world's oldest merchant bank, said the report must be taken with caution.
"But that details of the dinner have been so widely reported suggests that Brussels wants to send a clear warning to the UK: London will have to shift its positions substantially in order to clinch a deal with the EU27," he said.
May's official spokesman repeated Tuesday that "we approach the talks in a constructive manner and with a huge amount of goodwill".
"We will make a success of Brexit and we will secure a deal that works in the best interest of Britain and the European Union," he said.
Interior minister Amber Rudd, dismissing the report as "tittle-tattle", went further, warning that was a "mistake" to leak such details and saying Britain would be more discreet.
But Tim Farron, leader of the small, pro-European Liberal Democrat party, said the reports were a "taste of what's to come".
"The reports show a prime minister who is complacent and seems to have no idea how difficult these negotiations will be," he said.