Britain is considering legal action against Spain over the continued imposition of additional checks at the border with Gibraltar, Downing Street has said.
A No 10 spokesman said it was looking at the “unprecedented step” after the Spanish government failed to lift the extra controls over the weekend.
“Clearly the Prime Minister is disappointed by the failure of Spain to remove the additional border checks this weekend. We are now considering what legal action is open to us,” the spokesman said.
“This would be an unprecedented step so we want to consider it carefully before a making a decision to pursue.”
The move comes amid a worsening diplomatic row over the the construction of anartificial reef by the Gibraltarian authorities which Spain claims will destroyfishing in the area.
Madrid responded by beefing up border controls, leading to lengthy queues, and suggesting that a 50 euro (£43.30) fee could be imposed on every vehicle entering or leaving the British overseas territory through the fenced border with Spain.
Downing Street would not be drawn on what form any legal action would take, but confirmed that it would be done through Europe.
The spokesman said they believed the action by the Spanish – who have long challenged British sovereignty of the Rock – was “politically motivated and totally disproportionate” and therefore illegal under British law.
“If we go down this route, we will certainly press the EU to pursue the case as a matter of urgency,” the spokesman said.
No 10 thought that David Cameron had won an assurance from the Spanish prime minister Mariano Rajoy that the controls would be lifted over the weekend when they spoke last week.
The spokesman said that was still their understanding of the conversation, even though it was challenged by the Spanish.