A new major rift has emerged between the UK and the European Union concerning the post-Brexit relationship over Gibraltar. 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: …