Brussels is to insist that any Brexit delay is a one-off, according to senior EU diplomats, setting the stage for Theresa May to present MPs with the choice of her deal or a chaotic no-deal exit this summer.
The prime minister has suggested that she will seek a two-month extension if her deal is again voted down in the Commons in mid-March, to allow further time for negotiations.
But EU27 heads of state and government are said by senior sources to hate the idea of the UK then asking for a further delay when the initial extension proves to be insufficient for renegotiations.
May is expected to put her deal to the Commons again on 12 March, and then seek an extension of article 50 if it fails to pass.
EU diplomats say EU27 leaders will not want to discuss the length or terms of the delay when they meet for a European council summit on 21 March but merely sign off a mandated extension request made by May in the nine days after the vote.
The French president, Emmanuel Macron, said he would only agree to an extension, which would require unanimity of the EU27 leaders, if there was a clear purpose to it.
On Thursday, the Austrian chancellor, Sebastian Kurz, in a joint press conference with the EU’s chief Brexit negotiator, Michel Barnier, in Vienna told reporters: “If this extension should take place it is also necessary to ask the question: what is the goal for the time frame, what good does this extension do? Does it ensure that we will be able to finish all the work? But if this is the way out to prevent a hard Brexit then we will support this path.”
It is understood that May was told during recent discussions with Tusk and European commission president, Jean-Claude Juncker, that the Commons vote on 12 March, even if the meaningful vote is lost, should provide a clear path as to how the deal could be saved.
“A short extension without a mandate, or something from Westminster, will be very difficult,” one EU diplomat said. “If Westminster is not able to say anything, I don’t think the European council will buy it. What the European council will try to avoid is a discussion at the European council.
“She [May] has to pose the right question [with her request] to get the right answer. There are two schools of thought, one is that a short extension will be a short jump that will precede another extension – and this is something people hate. Politically and even from a purely administrative point of view. So others say it is better to have a long extension.”
A 21-month extension, delaying Brexit to 2021, is being pushed by some senior EU officials and diplomats to allow plans for the future relationship to develop, and for there even to be a change of personnel in Downing Street.
But there is resistance among member states who fear the EU will be blamed for trapping the UK in the bloc. “It is like playing the kingmaker, it isn’t sensible to intervene in domestic politics like that,” said one sceptic of the idea.
A delegation of Dutch MPs, who recently visited Westminster to examine the most probable outcome of the Brexit impasse, have reported to their parliament that a no-deal scenario know appeared “likely”. They warn that British MPs were “unable to reach agreement let alone make a proposal” to unlock the talks.