Foreign Secretary Dominic Raab said a draft mandate for talks published by the bloc on Tuesday “seeks to undermine the UK’s sovereignty” over the British overseas territory.
He demanded it “cannot form a basis for negotiations” as he urged the EU to “think again.”
But the bloc’s post-Brexit negotiator, Maros Sefcovic, said the mandate seeks to find a “positive impact” for those living either side of the border with Spain while protecting the single market.
Gibraltar, whose sovereignty is disputed by Spain and Britain, currently remains subject to the rules of the free-travel Schengen area, keeping the border with Spain open.
The territory was not included within the trade agreement brokered between the EU and the UK last year and a separate deal must be brokered.
In a statement, Raab said: “The UK, with Gibraltar, and Spain carefully agreed a pragmatic framework agreement, in full consultation with the EU commission.
“The commission’s proposed mandate, published today, directly conflicts with that framework. It seeks to undermine the UK’s sovereignty over Gibraltar, and cannot form a basis for negotiations.
“We have consistently showed pragmatism and flexibility in the search for arrangements that work for all sides, and we are disappointed that this has not been reciprocated. We urge the EU to think again.”
The European Commission said the proposed negotiating directives “put forward solutions to remove physical checks and controls on persons and goods” at the border between Spain and Gibraltar.
“It is without prejudice to the issues of sovereignty and jurisdiction, and focuses on cooperation in the region,” the bloc added.
The mandate includes rules for establishing responsibility for asylum, visas, residence permits, and police cooperation and information exchange.
Sefcovic, a commission vice-president, said: “By putting forward this draft mandate, we are honouring the political commitment we made to Spain to start the negotiations of a separate agreement between the EU and the UK on Gibraltar.
“This is a detailed mandate, which aims to have a positive impact for those living and working on either side of the border between Spain and Gibraltar, while protecting the integrity of the Schengen Area and the Single Market.”
By Sam Blewett