The incursion by a Spanish ship into British waters off Gibraltar is "provocative", "unlawful" and "a violation of our sovereignty", the Europe minister David Lidington has said.
David Lidington was speaking after a Spanish state research trip entered British waters along with a vessel belonging to the Guardia Civil, the part of Spain's police force responsible for protecting the coastline.
According to the United Nations Convention on the Law of the Sea, the waters around Gibraltar are indisputably British territorial waters, under United Kingdom sovereignty, in which only the United Kingdom has the right to exercise jurisdiction.
Her Majesty's Government takes a grave view of any attempt by Spain to exert authority or control within British Gibraltar territorial waters and considers such incursions as a violation of our sovereignty.
I strongly condemn this provocative incursion and urge the Spanish government to ensure that it is not repeated.
More top news
Tuesday: After a bright start, rain will gradually push northeastwards across England and Wales with strong winds developing.
Britain should have a second vote on the terms of exiting the EU if it can secure a new deal to control its borders, Jeremy Hunt has said.
Complaints have been lodged with the chairman of the 1922 committee over the neutrality of government whips.