Michel Barnier at a meeting yesterday with Josep Borrell, left, and Marco Aguiriano, the Spanish Secretary of State

Spain has threatened to reject the Brexit withdrawal agreement unless the European Union gives Madrid a guaranteed veto over a future trade deal between Britain and Europe.

Talks between European governments and Michel Barnier, the EU’s Brexit negotiator, over a blueprint setting out the broad terms of Britain’s future relationship have run into trouble.

Josep Borrell, the Spanish foreign minister, said that his government was ready to block the agreement at a summit this weekend unless it was given a cast-iron promise that no future trade or security deals would apply to Gibraltar without Spain’s consent.

“Negotiations between the UK and the EU do not apply to Gibraltar. Future negotiations on Gibraltar are separate negotiations,” he said

“That is what must be made clear. Until