Spain was accused of an “act of war” today after its naval ships repeatedly entered the territorial waters of Gibraltar.

Bob Stewart, Tory MP for Beckenham, said the British Government needed to "respond robustly to this aggravation" after Commons Leader Andrew Lansley said two Spanish naval vessels entered the waters of Gibraltar on Monday.

He said they were given radio warnings before leaving but Mr Stewart, a former colonel, said the incursion was illegal and the Government needed to "do something about it".

Defence Secretary Philip Hammond and Foreign Secretary William Hague should update the Commons with a statement, he said.

Speaking in the Commons, Mr Stewart told MPs: "May I gently remind the House that an illegal incursion into British Gibraltarian sovereign waters is actually, technically an act of war?

"What is happening at the moment is wrong and we should do something about it.

"Can I ask for an urgent statement by the Secretary of State for Defence and the Secretary of State for Foreign Affairs to actually respond robustly to this aggravation?"

His comments came after his Tory colleague Andrew Rosindell, MP for Romford, said Spain needed to be stopped immediately.

In his question to Mr Lansley, he said: "I am sure the entire House will be shocked, angered and dismayed at the continual incursions by the Spanish government into the waters around the British sovereign territory of Gibraltar.

"This is an act of aggression and will you ask the Secretary of State for Defence and Secretary of State for Foreign Affairs to make a statement about what Her Majesty's Government will do to ensure these illegal incursions into British sovereign waters are stopped forthwith?"

The Commons Leader said the Government had protested to Spain through diplomatic channels.

He told Mr Rosindell: "I can tell you there were two incursions by Spanish naval vessels into British Gibraltar territorial waters on December 10.

"Radio warnings were issued and the vessels departed from those waters.

"We have protested to Spain via diplomatic channels.

"The Royal Navy challenges Guardia Civil and other Spanish state vessels whenever they make unlawful incursions into British Gibraltar territorial waters and we will back those up by making formal diplomatic protests to the Spanish government.

"They will make clear that such incursions are an unacceptable violation of British sovereignty."

In a written parliamentary question earlier this week, Mr Rosindell discovered that the number of incursions had spiked this year.

Responding to the question, Defence Minister Andrew Robathan said there were 67 instances in 2010 and another 23 last year. But from the beginning of January to the end of November this year there had been 197 occasions when Spanish ships had sailed into the waters of Gibraltar.

Last month a Freedom of Information request from the Press Association revealed that the illegal incursions had prompted a flurry of complaints from the Foreign Office to the Spanish government in Madrid.

There had been 42 formal written complaints to the Spanish Ministry of Foreign Affairs since 2008, half of which were submitted in the last 12 months. The issue has also been raised directly with ministers and officials.