Theresa May greets European Commission President Jean-Claude Juncker as he arrives at 10 Downing Street on April 26, 2017 | Carl Court/Getty Images May’s Brexit gambit leaves Brussels mystified British PM seeks to enlist Commission President Juncker and top negotiator Barnier as her new allies in Brussels.

LONDON — At least there was an agreement about no leaks.

When U.K. Prime Minister Theresa May and European Commission President Jean-Claude Juncker last shared an intimate dinner focused on Brexit, it was a debacle. Leaks from the Brussels side claiming May was "deluded" about Brexit infuriated London, sparking condemnation on the steps of Downing Street by the PM.

This time, the two sides issued a joint statement that twice pronounced the dinner "constructive" while also agreeing divorce talks needed to "accelerate" over the next few months.

But it was a sign of just how badly the negotiations have gone that according to officials familiar with the dinner discussion Monday night, May and her advisers sought to enlist Juncker and his top negotiator, Michel Barnier, as Britain's new allies in Brussels.

Two senior aides, who spoke to POLITICO on condition of anonymity, said the prime minister hoped to convince Juncker to press the leaders of the EU27 to expand Barnier's negotiating mandate and to help convince them May could not make any more concessions after her speech in Florence last month. It comes after her efforts to lobby French President Emmanuel Macron and German Chancellor Angela Merkel appeared to hit brick walls in Paris and Berlin this week.

One U.K. official explained the goal of the dinner: "She doesn't have any more room for maneuver so they have to help create it for her."

But if May came to Brussels looking for Juncker to take a softer line, that approach left officials in the EU capital mystified. Even if Brussels is not quite "the enemy" as Chancellor Philip Hammond recently suggested, Juncker isn't in much of a position to extend a helping hand.

EU officials believe they have already created a path for May to secure a transition deal and start talks on the framework of a future trade relationship at the next European Council meeting — provided the divorce terms of Brexit are settled by December.

The EU27 leaders in the European Council seem prepared to draft conclusions at a summit meeting Friday that would make it clear the bloc is preparing for just that path. But May first has to do her part by clarifying what she meant in her Florence speech about the U.K. meeting its financial obligations and resolving differences over citizens' rights and Northern Ireland.

Brussels sees little reason for London to quibble over the issues — Juncker himself last week called the arguments over citizens' rights "silly."

Yet in Westminster there is growing frustration at the inability of EU leaders to grasp that the divorce settlement cannot be negotiated in isolation.

On Northern Ireland, in particular, the question of how a future border with the Republic will work is entirely dependent on the relationship Britain is able to negotiate with Brussels on customs, U.K. negotiators have sought to stress.

More politically, May and her team do not believe they can commit to a financial settlement with Brussels unless they have an idea of what will come at the end of the talks.

To Brussels this is a fundamental misreading of the situation. Juncker, Barnier, Council President Donald Tusk, Macron, Merkel and the rest of the 27 see simply a request for clarification about the financial obligations May said the U.K. was prepared to fulfill.

May could be forgiven for trying. Locked out of the Council's discussion on Brexit on Friday and battered by political critics at home, she correctly identified that Barnier, at least, is committed to finding a solution. Officials in Brussels have repeatedly expressed sympathy for May's political predicament, but stressed they cannot break EU treaty obligations to help her.

Senior Commission and Council officials said they had nothing to add to the joint statement by May and Juncker.

One official, asked if there was any further insight into May's goals in coming to Brussels, replied cheekily: "Nope, but it was a constructive and friendly dinner."

In the U.K. there was satisfaction with the joint statement, which hailed both sides' determination to progress the talks.

The text was drafted after an early evening dinner in the Commission’s Berlaymont building in Brussels involving the two leaders plus key advisers on Brexit and the EU’s chief negotiator Barnier.

May arrived in Brussels for the informal discussions — which also included the Iran nuclear deal, counterterrorism and preparations for the upcoming European Council summit — aiming to “stiffen the spines” of the European Commission.

With the prospect of moving the Brexit talks on to phase 2o — the U.K.’s future relationship with the bloc and trade — now off the table at this gathering of EU leaders, the U.K. is keen to ensure the green light does happen at the next summit in December.

May will return to Brussels Thursday to participate in the European Council summit.