British warships began setting sail for the Mediterranean on Monday for a naval exercise that will see one vessel dock in Gibraltar, as tensions rise with Spain over the British-held territory.
Helicopter carrier HMS Illustrious steamed out of Portsmouth, to be followed on Tuesday by the type-23 frigate HMS Westminster, which is set to arrive in Gibraltar, at Spain's southern tip, within a week.
Also heading for the exercise codenamed Cougar '13 is amphibious vessel HMS Bulwark and the HMS Montrose frigate as well as six supporting vessels.
The Ministry of Defence has stressed that the deployment of the ships is "routine" and "long-planned".
Madrid has agreed to allow HMS Illustrious to stop at a naval base in Rota in southern Spain as part of the operation, but Spanish media have described the plan for HMS Westminster to put in at Gibraltar as an intimidation.
Britain and Spain are embroiled in an escalating diplomatic row over stringent car searches by Spanish guards at the Gibraltar border, causing tailbacks of several hours.
The government of the tiny peninsula has accused Madrid of acting in retaliation after Gibraltar built an artificial concrete reef which it says is aimed at stopping alleged incursions by Spanish fishing boats.
Writing in The Sun newspaper on Monday, Britain's Europe minister David Lidington said: "Britain and Spain matter to each other. We are Nato allies, key trading partners and millions of Brits travel to Spain every year.
"But our good friendship with Spain does not mean we will turn a blind eye when the people of Gibraltar are threatened or put under pressure."
Spanish Prime Minister Mariano Rajoy said on Friday that Spain would take "all necessary measures" to defend its interests in Gibraltar and backed the border checks, which Madrid says are necessary to combat smuggling.
But he added that the British navy manoeuvres had already been announced in June and that several British naval ships had stopped in Rota in recent years.
"Bilateral ties with Britain are good and we want then to remain so in the future. This has nothing to do with what is going on right now in Gibraltar where I hope common sense will prevail," he said.
The British defence ministry said the Cougar '13 deployment would allow its navy to "hone its world class maritime skills thousands of miles from home through exercises with a number of key allies".
The ships will visit a number of Mediterranean ports, carrying out an exercise with the Albanian armed forces before heading through the Red Sea, Indian Ocean and Arabian Gulf for exercises with other British allies.
Spain ceded Gibraltar to Britain in perpetuity in 1713 but has long argued that it should be returned to Spanish sovereignty. London says it will not do so against the wishes of Gibraltarians, who are staunchly pro-British.
The self-governing British overseas territory, measuring just 6.8 square kilometres (2.6 square miles), is home to about 30,000 people and is strategically important as it overlooks the only entrance to the Mediterranean Sea from the Atlantic Ocean.
Date: Aug 12, 2013