The president of the European Commission, Juncker, told reporters May already knows and accepts that the Union will not re-open talks on the deal.
And Tusk, who represents EU member governments as head of the European Council, triggered outrage across the Channel by damning pro-Brexit politicians for — in his view — recklessly failing to plan.
“I’ve been wondering what that special place in hell looks like, for those who promoted Brexit without even a sketch of a plan how to carry it out safely,” Tusk said.
Juncker, at a later news conference, did not use the same language, but cheerfully laughed off Tusk’s remark.
But he also repeated the same warning that the withdrawal agreement, and the backstop clause designed to keep the Irish border open if no future trade deal is agreed, will not be changed.
“She knows that the commission is not prepared to reopen the issue,” Juncker said, after talks with Irish Prime Minister Leo Varadkar, who also insisted on the need for the backstop.
This apparently united front did not daunt Number 10, who insisted that the British parliament’s rejection of the deal meant that May must seek material changes to the accord or see it fail.
According to talking points provided by Downing Street ahead of the visit, May will admit that: “Securing such changes will not be easy.”
But she will add: “Last week, Parliament made clear that for the first time it could support the withdrawal agreement, subject to changes to the backstop.
“The Government now wants urgently to work with the EU to secure such changes. The EU shares the UK’s commitment to leave with a deal. We must show determination and do what it takes to now get the deal over the line.”
The impasse in Brussels has led to heightened fears Britain could crash out of the EU without a deal on March 29, disrupting trade and supplies to manufacturing.
Tusk and Juncker said they look forward to hosting May on Thursday, and Varadkar will have dinner with her in Dublin on Friday.
Offering warm support for his Irish guest, Tusk said the European Union “will not gamble with peace” on the Irish border by removing the backstop from the deal.
“I hope that tomorrow we will hear from Prime Minister May a realistic suggestion on how to end the impasse,” he said.
But he added: “A sense of responsibility also tells us to prepare for a possible fiasco.”
Varadkar, whose government has stressed the importance of maintaining an open border between Ireland and Northern Ireland after Brexit, thanked Tusk.
“While we expect the backstop will never be used, we agreed again today it is needed as a legal guarantee to ensure there is no return to a hard border,” he said.
On Wednesday, May discussed the issue with Northern Irish leaders in the British province.
Last month, the House of Commons overwhelmingly rejected the Brexit deal that May had negotiated with the EU after 18 months of painstaking diplomacy.
May is now looking into changes to satisfy her MPs, who fear the backstop would keep Britain indefinitely tied to EU rules with even closer alignment for Northern Ireland.
May’s spokesman stressed that she wasn’t coming to Brussels to ask for more time and remained determined to deliver a Brexit deal before the March 29 deadline.