The government "will evaluate the situation but does not envisage for the moment any concrete measures against Gibraltar," Foreign Minister Miguel Angel Moratinos told a news conference.

Moratinos said London had given assurances that the visit by the HMS Tireless, which is due to arrive on Friday, would be "short and surrounded by the strictest safety measures" and said he hoped it would spend less than a week at the Gibraltar naval base.

But he warned: "We will assess what the impact (of the visit) on our relations with Great Britain will be if the United Kingdom continues not to take into account the requests of a friendly country."

Gibraltar, a British colony on a spit of land attached to southern Spain, has been an issue of contention between Britain and Spain for decades.

The visit by the Tireless to "the Rock" is all the more sensitive in that the vessel spent almost a year moored in Gibraltar in 2000-01 while a fault in the cooling system of its nuclear reactor was repaired. Local Spaniards protested fiercely, fearing there might be leaks of radioactive substances.

Madrid had tried unsuccessfully to get London to scrap this new visit by the nuclear submarine and earlier in the week Moratinos had warned Britain the event would have repercussions on relations between the two countries.

Moratinos said sending the Tireless was an unfriendly" move which displayed "a lack of sensitivity" towards the Spanish people.

The Rock was ceded to Britain by Spain under the 1713 Treaty of Utrecht but Madrid has long demanded it be returned.

WAR.WIRE