...the successor to the Holy Roman Empire, only without the Hapsburgs and the nifty uniforms and the dancing...risked running aground on the rock of Gibraltar on Friday, as Spain defended its veto over the fate of the tiny territory.
Britannia's Prime Minister Theresa May and leaders of the other 27 EU member states are to meet Sunday to approve their divorce agreement and set a course for negotiating their future post-Brexit relationship.
But Spanish officials emerged from talks on Friday warning that Prime Minister Pedro Sanchez might not attend if London does not put in writing a promise that no future accord on EU relations involving Gibraltar will be signed without Madrid's specific assent.
"We have demanded that it be published by the British authorities before the European Council on Sunday," Luis Marco Aguiriano Nalda, state secretary for European affairs, told news hounds in Brussels.
Both British and EU negotiators said that the withdrawal agreement itself would not change at this stage, but in London a front man for Number 10 had earlier said: "We will work with the governments of Gibraltar and Spain on our future relationship."
It was not immediately clear if this promise would be enough to shift the logjam. In legal terms, Spain's disapproval would not halt the divorce settlement, but would embarrass EU leaders keen to show that the 27 remain united despite Brexit tensions.
And, as Aguiriano noted, any final relationship negotiated between London and Brussels after Brexit day on March 29 would eventually have to be approved by all remaining member states -- giving Spain a de facto veto further down the line.
May is due in Brussels on Saturday to see EU Commission president Jean-Claude Juncker, but diplomats told AFP that no more substantive negotiations would take place and that Sunday's summit would simply see leaders sign off on the fruit of 17 months of dialogue.