British warships arrived in Gibraltar on Monday (August 19) for scheduled exercises amid tensions with Spain over fishing around the British Mediterranean enclave.

Although British, Spanish and Gibraltarian authorities have said the navy's arrival at the British overseas territory is long-scheduled, some in Spain see it as provocative.

At about 0715 GMT the frigate HMS Westminster was seen approaching the port of Gibraltar flanked by two smaller ships.

Gibraltar's creation of an artificial reef with concrete blocks, which Spanish fishermen say blocks their access to certain waters, has prompted Spain to toughen its border checks, leading to long queues for workers and tourists entering Gibraltar.

On Monday, Gibraltar Chief Minister Fabian Picardo accused the Spanish government of creating conflict to distract attention from corruption allegations against the ruling People's Party.

Picardo said the concrete reef was necessary to help marine life recover from overfishing.

As well as tightening border controls, Spain has threatened to charge tourists a 50 euro ($67) border levy, restrict the use of Spanish air space or block Gibraltar's lucrative ship fuelling business.

While Spain has threatened to take its claim to Gibraltar to the United Nations, Britain has asked the European Commission urgently to send monitors to verify whether the border checks breach EU rules.

Presented by Adam Justice