In a major diplomatic victory for Madrid, the EU's draft guidelines for Brexit talks with Britain state that any divorce deal that applies to Gibraltar will require the approval of both the United Kingdom and Spanish governments.
Britain and Spain have engaged in centuries of squabbling over the territorial status of "the rock", and the EU's stance is likely to intensify those arguments.
But residents overwhelmingly voted to remain with Britain in two sovereignty referendums in 1967 and 2002.
"It is shameful that the European Union have attempted to allow Spain an effective veto over the future of British sovereign territory, flying in the face of the will of the people of Gibraltar", said Lopresti.
Both the British and Gibraltar governments rejected the both possibility of the island being shared between Britain and Spain and the unlikelier prospect of it returning to total Spanish control. Citizens of the rock - who overwhelmingly reject Spanish rule - will be concerned that the European Union apparently wants to allow Spain to sign off on the Brexit arrangements that concern them.
"We have been firm in our commitment never to enter arrangements under which the people of Gibraltar would pass under the sovereignty of another state against their wishes, nor to enter into a process of sovereignty negotiations with which Gibraltar is not content", she said.
Esteban González Pons, the vice-chairman of the European People's Party, told Spain's El Pais newspaper this omission was "very relevant", adding: "Gibraltar isn't part of the United Kingdom".
Tom Brake the Liberal Democrat foreign affairs spokesman said: "Confirmation that Gibraltar's future must be agreed by the United Kingdom and Spain shows just how damaging the Government's hard Brexit will be on this strategically important British territory".
But, while the new Foreign Minister's comments will provide some comfort to those who have to cross the frontier into Gibraltar to work, CM Picardo has warned that Spain's sovereignty objective remains unchanged.
Known as "the rock", Gibraltar is home to 30,000 people.
This detail is key as it means Prime Minister Theresa May and acting Spanish Prime Minister Mariano Rajoy may have to hold bilateral discussions over the territory if any points of contention arise during Brexit negotiations.
"Theresa May must urgently produce a plan that protects the citizens of Gibraltar, including their businesses and communities".
He added that there was no question of any negotiation over Gibraltar's future and said he would raise the matter with the secretary general of North Atlantic Treaty Organisation.
"It's predictable that, given Spain's previous behavior, they would try and use Brexit as a fig leaf for trouble-making over the status of Gibraltar", Lopresti said Friday.