Image caption Spain disputes UK sovereignty over Gibraltar

Britain is reviewing its navy options in Gibraltar after an illegal incursion into its territorial waters on Monday, a Foreign Office minister has said.

Mark Simmonds told the Commons a Spanish state vessel, the RV Romon Margalef, was accompanied across the border by three Guardia Civil boats.

The vessel failed to leave Gibraltan waters for 22 hours despite requests, and was challenged by the Royal Navy.

Spain's ambassador to the UK was called to the Foreign Office to explain.

Mr Simmonds said the Spanish vessel had come within 250 metres of the entrance to Gibraltar Harbour.

During the incident, the RV Ramon Margalef said it had been "carrying out oceanographic works" that were "of the European Community interest".

'Nothing off table'

On Wednesday, Mr Simmonds was called to the Commons to answer an urgent question on Gibraltar by Conservative MP Bob Neill.

Mr Simmonds said an escalation of tensions was "in nobody's interests", and that it was a "political solution that is required to [end] this dispute".

Image caption The European Commission ruled that border checks had not broken EU laws

However, he added: "Of course, nothing is taken off the table. We constantly review the naval presence in and around Gibraltar and certainly we are doing so now."

The UK government believes that the waters around Gibraltar are indisputably British territorial waters.

But Spain disputes UK sovereignty over Gibraltar, a limestone outcrop known as the Rock near the southern tip of the Iberian peninsula, which has been ruled by Britain since 1713.

Mr Simmonds said the UK stood "ready to do whatever is required to protect Gibraltar's sovereignty, economy and security".

"We believe it is in the interests of Spain, Gibraltar and Britain to avoid incidents such as this which damage the prospects for establishing dialogue and co-operation," he said.

Spain's ambassador to the UK, Federico Trillo, was summoned to the Foreign Office on Tuesday where he met acting permanent under-secretary Matthew Rycroft, MPs were told.

It is the third time the Spanish ambassador has been publicly summoned over the conduct of Spain towards Gibraltar since Spanish Prime Minister Mariano Rajoy's government took office in December 2011.

Reef row

Mr Simmonds said that during the meeting, the Foreign Office had underlined the British government's "serious concerns regarding this provocative and unlawful incursion by a Spanish-state research vessel".

Media playback is unsupported on your device Media caption Mr Simmonds said the UK government has "serious concerns"

He also said the ambassador had been "again reminded of our continued concerns regarding border delays which continue on a near-daily basis", as well as the UK's desire for positive ad-hoc talks - proposed by the foreign secretary in 2012.

Last week, the European Commission ruled that checks by Spain at the Gibraltar border had not broken EU laws.

Madrid had imposed strict controls at the border that Britain and Gibraltar had argued were politically motivated.

Gibraltar said the strict checks came after it dropped 74 concrete blocks into the sea next to its territory, intended to create an artificial reef and encourage sea life to flourish.

Spain said the blocks would disrupt waters used by its fishing boats, but denied that the development had prompted its increased border checks.

It said stricter checks at the border were being enforced to combat tobacco smuggling to Spain from Gibraltar - where cigarettes are around 40% cheaper.

Correction 13 December 2013: This story has been amended to clarify that it is the UK government's view that the waters around Gibraltar are 'indisputably British territorial waters'