Senior officials said it is extremely unlikely that EU leaders will agree to adapt the legal framework they handed down to the Frenchman so that he can begin talks on a transition.
Mr Barnier is said to be frustrated with the limitations of his mandate and recently told a meeting of prominent MEPs he has the “resources” to begin scoping the future partnership immediately but is being “restricted legally from doing so”.
The Frenchman is believed by some to have privately come to the conclusion that the talks will remain deadlocked over certain issues, including the Brexit bill, until he is allowed to offer Britain an olive branch.
He is widely reported to have asked the member states to allow him to start trade talks with Britain at recent top-level meetings, but has failed to secure the unanimity required to forge ahead so far.
The Frenchman is believed to have earned the support of “almost all” EU countries for his compromise position but has been rebuffed by hardliners France, Germany and Romania.
British politicians, including the Brexit secretary David Davis, have repeatedly said the EU needs to show more “flexibility” to overcome the hurdles blocking progress.
But today diplomats revealed there is still little appetite in those more stubborn capitals to accede to any such request at the next meeting of the European Council of 27, which takes place later this month.
Briefing journalists ahead of a meeting of the General Affairs Council (GAC) next week, a top Brussels official also ruled out any chance of “sufficient progress” on the divorce being agreed this month.
She said: “We don’t see the need to change the mandate at this moment and the mandate very clearly says that there will be no trade talks and no transition talks until the first phase of the negotiations has been concluded.
“If our political leaders feel the need they will discuss it in the European Council but frankly I don’t see this forthcoming at the moment. So we don’t really expect that the ministers in the GAC are going to take any groundbreaking decisions here.
“If Mr Barnier will somehow be empowered by us to take that transition period with the UK I don’t know, this is for the EU Council to decide. I would be surprised if there is sufficient ground for us give him an official mandate to do this, because this would mean mandate change.”
However, despite declaring that she could formally rule out the prospect of a “sufficient progress” vote – which would unlock trade talks – at the October summit the diplomat was still upbeat about the talks.
She told reporters: “There is no sufficient progress, the atmosphere is there’s no sufficient progress. On the other hand I don’t think it’s a blow that we need to soften, this is just a state of play.
“The negotiations are taking time, this is perfectly normal for any negotiations. In hindsight I think the timescale for reaching anywhere in October was pretty optimistic to start with.”
Asked about the possibility of a no-deal scenario, she added: “ I can honestly say generally speaking there’s a very constructive mood amongst the ambassadors and this is something we’d hope to see in the GAC.
“I think our leaders have quite recently very clearly said that this is certainly not something that the EU intends to do. We’re also rather reluctant at any time and on any topic to prepare us for a possible trade crash or a possible apocalyptical scenario.
“The EU is at its best when it’s working towards a compromise and of course there is a very good basis for us to hope that we will find such a compromise between the UK and the EU.”