The way forward for the British territory is a serious excellent downside for Mrs Could, with Spanish Prime Minister Pedro Sanchez threatening to vote towards the Brexit settlement over the row.
Spain is demanding that the way forward for the Rock is settled by means of direct talks between London and Madrid.
However diplomats in Brussels have accused Mr Sanchez of attempting to attain factors with voters forward of a regional election in Andalusia – which shares a border with Gibraltar – on December 2.
One main diplomat advised Politico: “It appears Sanchez has his eyes on the elections in Andalusia.”
The vote shall be socialist Mr Sanchez’s first take a look at underneath his management and a powerful worldwide battle will possible increase his reputation within the vote.
It comes after Mr Sanchez vowed to vote towards the Prime Minister’s Brexit settlement until the bitter dispute is resolved.
The Spanish Prime Minister stated that his authorities was “irritated” that the divorce deal didn’t state that Gibraltar’s future could be determined between Spain and London.
Mr Sanchez added: “If this isn’t solved by Sunday, Spain, a pro-European authorities, will sadly must vote ‘No’.”
Fellow EU nations are livid with Mr Sanchez’s stance with Eire’s international minister Simon Coveney saying: “If you happen to reopen [the Withdrawal Agreement] for one situation, properly then there may be an avalanche of different asks, I’m positive, that totally different international locations can have.”
And an EU diplomat added: “We’re following the newest developments with rising concern and incomprehension.”
However final evening Mrs Could insisted that there had been “good engagement” between the UK, Spain and Gibraltar.
A Downing Avenue spokesman stated: “She stated there had been good engagement between the UK, the federal government of Spain and the federal government of Gibraltar as a way to come to an settlement within the withdrawal settlement and related package deal of memoranda of understanding regarding Gibraltar.
“She stated that the UK and authorities of Gibraltar seemed ahead to those discussions persevering with as we focus on the longer term relationship.
“The Prime Minister reiterated her dedication to agreeing a deal that works for the entire UK household together with Gibraltar, the opposite UK abroad territories and the crown dependencies.”
The problem of Gibraltar is believed to be the ultimate impediment from EU leaders that Mrs Could faces.
Earlier considerations over fishing and commerce have been addressed, in line with an EU diplomat.
The supply stated: “The one factor actually excellent is Gibraltar.”
Mrs Could is returning to Brussels on Saturday for crunch talks with European Fee President Jean-Claude Juncker forward of the leaders’ summit.
Gibraltar has been a British territory since 1713 however Spain has lengthy claimed sovereignty.
Within the 2016 EU referendum 96 % of Gibraltar’s inhabitants voted to reman within the EU.