"It was met by the Gibraltar Squadron and invited to leave".
Tuesday's was the seventh incursion by a Spanish navy ship this year, according to Gibraltar's government.
After an European Union document suggested that Spain would be given a say on post-Brexit agreements governing the British overseas territory, Lord Howard said he was certain that the Prime Minister would be ready to defend the Rock as Margaret Thatcher did the Falklands.
THE UK won't enter new agreements with the European Union if the Spanish government try to exclude Gibraltar.
Tensions soared after Gibraltar built an artificial reef in 2013 that Spain said hurt its fishermen. Some 10 thousand persons go to work daily in Gibraltar, that depends on its small land border with Spain to trade and receive visitors and workers.
It comes a day after Spanish foreign minister Alfonso Dastis told the United Kingdom not to "lose tempers" after the EU Brexit negotiation guidelines effectively gave Spain significant power over Gibraltar's future.
David Parody, a resident of Gibraltar, tweeted a picture of the boat with the caption, "In true Spanish style, to calm down, they send us a gun boat".
"We are going to be talking to them about getting the best possible deal for the United Kingdom and for those countries, Spain included".
Lord Howard repeatedly compared the situation to the Argentine invasion of the Falkland Islands that led to war with the United Kingdom in 1982.
'Our position on the sovereignty of Gibraltar has not changed and will not change, ' she added.
Theresa May and Foreign Secretary Boris Johnson have moved to reassure the people of Gibraltar that the territory will remain under British control. It said that one of the two patrol vessels that Britain's Royal Navy keeps in Gibraltar chased the Spanish ship off. In declarations to reporters, the Spaniosh minister of Foreign Affairs, Alfonso Dastis, showed this Monday its surprise over the tone of the government of Prime Minister Theresa May, regarding the mentioned territory of seven square kilometers.
"The Prime Minister said that we will never enter into provisions whereby the people of Gibraltar see their sovereignty transferred to another state against their freely and democratically expressed wishes, nor will we ever enter into a process of sovereignty negotiation with which Gibraltar is not satisfied", the spokesman said.