HMS ILLUSTRIOUS is leading a Royal Navy flotilla of 13 vessels during a huge NATO exercise off the coast of Portugal.

Exercise Linked Seas, from May 2 to May 15, involves over 30,000 NATO personnel, 80 warships, 20 support vessels, 120 aircraft and five battalions of multi-national land forces.

Illustrious will be joined by the destroyers HMS Glasgow, Liverpool, and Gloucester, frigates HMS Campbeltown, Northumberland and Westminster, minesweepers HMS Chiddingfold, Quorn and Penzance, the Swiftsure-class submarine HMS Sovereign and RFAs Fort George and Sir Galahad.

They will be operating off France and Portugal in the Bay of Biscay, Quiberon Bay, the Iberian Peninsula and the Madeira Archipelago as they play out a scenario designed to test their ability to operate in a multi-national force.

Exercise Linked Seas will see NATO land, air and maritime forces being called in to enforce a UN-brokered cease-fire between two non-NATO nations who have gone to war with each other.

NATO land forces will be introduced to help defuse the situation and although the scenario is fictitious there are strong parallels between the requirements of the exercise and the skills needed in real-life operations in Bosnia, Croatia and most recently in Kosovo.

Twelve NATO nations are taking part, Belgium, Canada, Denmark, France, Germany, Italy, the Netherlands, Portugal, Spain, Turkey, the UK and the USA, and they will be joined by five Eastern European nations who have signed up to NATO's Partnership For Peace (PFP) initiative.

During the exercise, which will begin in six separate geographical locations, FA2 Sea Harriers from HMS Illustrious will be operating alongside RAF GR7 ground attack aircraft. They are expected to engage in cross-deck operations with the Spanish navy and will be operating together for the first time under the command of the new Joint Force 2000.