When Olly Robbins, the prime minister’s Brexit point-man, was spotted arriving at Brussels-Midi train station shortly after Theresa May had postponed the “meaningful vote”, British officials were quick to insist it was a routine meeting.

In reality, the Downing Street aide was in town for the start of secret, intensive talks with two of the EU’s most senior officials, Piotr Serafin from Donald Tusk’s European council, and Martin Selmayr, the secretary general of the European commission, in an attempt to stage-manage an EU rescue of the prime minister’s Brexit deal.

Theresa May says there will be further Brexit talks with the EU – Politics live Read more

In something of a rerun of May’s nightmare in Salzburg in September, and in a development all too familiar to the Brexit negotiations, things were to go badly wrong.

May went into the EU leaders’ summit on Thursday believing a two-stage process for helping her to sell the deal back in parliament was in play.

Robbins and the EU officials had discussed a communique that the EU27 leaders would issue soon after their meeting with the prime minister and an internal discussion without her over a dinner.

The statement would say that the backstop, keeping the UK in a customs union in order to avoid a hard border on the island of Ireland, was an “undesirable” outcome. It would only ever be in place for a “short” period, if at all.

Crucially, they would pledge that the EU was “ready to examine whether any further assurance can be provided”. Hard copies of the document had been circulated among EU ambassadors on Wednesday, with security watermarks put on the paperwork to guard against leaks.

British officials only saw a final draft on Thursday morning but were happy with this as the first step. It was seen as paving the way to a second stage involving the negotiation of a “joint interpretative instrument” to the withdrawal agreement, which would emerge in January as the bombshell breakthrough to “get the deal over the line”. The UK wants a 12-month limit placed on the backstop, should it ever come into force, to convince the deal’s critics that they won’t be trapped in a customs union.

But, as one senior EU official had warned, the leaders were a “tough crowd”. May irritated many of them straight off by saying in her address before dinner that “we are at the beginning of a negotiation”. They objected to her suggestion that the bloc was embarking on a new process to help the withdrawal agreement pass through the British parliament. “The EU doesn’t want to shoulder the whole responsibility of having to muster unicorns or do magic,” an EU source said.

May talked to them about the legal instrument she thought could help: one used previously to persuade the Belgian region of Wallonia to accept the EU-Canada free-trade deal, and the Dutch to pass the EU-Ukraine agreement, following initial rejection by popular vote.

But, said an EU diplomat, “all these examples were taken by the EU28 to help one of their members – but it was never for Canada or Ukraine, it was to facilitate ratification on the EU side. There is no guarantee that what we would do would help Theresa May in parliament.”

Fearing exhausting and ultimately pointless negotiations, leaders agreed within minutes to scrap a line in the draft text that the EU “stands ready to examine whether any further assurance can be provided” on the backstop. Also quickly agreed was an extra line requiring the UK to do its utmost to avoid the backstop, rather than putting all the onus on the EU.

Denmark’s prime minister, Lars Løkke Rasmussen, told leaders that the British parliament had failed to look for a way to solve its problems, as Denmark did following its rejection of the Maastricht treaty in 1992.

Facebook Twitter Pinterest Lars Løkke Rasmussen (C) arrives for the summit in Brussels. Photograph: Emmanuel Dunand/AFP/Getty Images

One EU leader was reported to have said he did not believe many MPs had even read the withdrawal agreement. Belgium’s prime minister, Charles Michel, repeated his concern that the Brexiters would just come back for more. “The Belgians describe it as a carousel,” a diplomat said.

“It wasn’t so much about her, it was the fact that she couldn’t find the right answers,” said a source. May could not explain how inserting an aspirational time limit on the backstop would help both sides reach a trade deal faster. “I don’t buy the ‘she bodged it’ line. Everyone is following UK politics, they just don’t believe that she can get [the deal] through.”

The communique, when published, was not the helpful document it had been. A roadblock appeared to have emerged over the second stage in January. But worse was to come.

Addressing reporters at a midnight press conference, Juncker went off-script. He told of a lack of clarity on the UK side, a jibe that the British officials felt was disingenuous given the level of back-channelling.

“Our UK friends need to say what they want, rather than asking what we want,” he went on. “We would like in a few weeks for our UK friends to set out their expectations because this debate is sometimes nebulous and imprecise and I would like clarifications.”

Aides to Tusk were appalled. The prime minister was certainly not amused. The next day, a TV camera caught her in a frosty exchange with Juncker. “What did you call me?” an agitated May asked the commission president. “You called me nebulous.”

Play Video 0:23 Theresa May and Jean-Claude Juncker have 'frosty exchange' – video

Flustered, Juncker denied it, putting his hand on the prime minister’s arm to defuse the situation. Later, at her own press conference on Thursday afternoon, May denied that her pledge to MPs to secure “legal and political assurances” of the temporary nature of the backstop was dead in the water. But so little seems to be going to plan. It is likely to be an anxious Christmas in Downing Street.