A no-deal in Brexit talks over Gibraltar will hurt Spain, forcing its workers to endure 14-hour queues to get to their jobs on the Rock, the mayor of a Spanish border town has warned.

Juan Franco told the Telegraph that some of the 11,000 Spaniards entering Gibraltar every day would inevitably be drawn to the region’s organised criminal gangs if they could no longer work on the British overseas territory.

No deal would trigger a hard border. This means passport stamps, which have been waived since Brexit to buy time for negotiations, would be enforced, the mayor of impoverished La Linea, which neighbours Gibraltar, said.

“At that moment the whole system will explode,” Mr Franco said, citing chaotic scenes at the border last Friday after Spanish guards began stamping passports in a surprise move.