Spanish vessels and helicopters were in “clear violation of the international law” after entering UK waters in Gibraltar, the Foreign Office has said.
Spanish police chasing criminals have made several incursions into British waters in the past two days, it added.
The Royal Navy escorted the Servicio de Vigilancia Aduanera (SVA) – Spanish police’s drugs and money laundering squad – out of the waters.
Minister Hugo Swire said the incursions were “completely unacceptable”.
He said: "On 9 August Spanish state vessels repeatedly entered British Gibraltar Territorial Waters without notifying Gibraltarian authorities.
“We understand that the Spanish were in pursuit of vessels who may have been committing crimes. However it is completely unacceptable and unlawful under the international law of the sea to enter our waters without notifying us.”
He described the “repeated incursions into British Gibraltar Territorial Waters” as a “clear violation of UK Sovereignty by another EU country”.
The UK would be raising the issue as a matter of urgency with the Spanish authorities, he added.
