TROOPS, armed police and even the intelligence services could operate in Southampton docks in a future national terrorist emergency.

UK ports, including Southampton, form a vital part of the country's front line in the war against terrorism and a new comprehensive security regime, set to come into force in July of next year, is now being worked on by the government.

This comes as Southampton's key maritime position for the nation is highlighted with the port playing a vital part in the military build-up of the British task force that would go into action in any future conflict with Iraq.

Yesterday, four Royal Fleet Auxiliary vessels sailed from the city bound for the Mediterranean where they will join a task group, led by the carrier HMS Ark Royal.

RFA landing ships Sir Percivale, Sir Galahad and Sir Tristram left Marchwood Military Port in the morning with Royal Marines, vehicles and weapons on board. Then, in the afternoon, the helicopter carrier and hospital ship RFA Argus embarked five Sea King Mk6s and left in the late afternoon.

Southampton, one of the fastest growing trading centres in Europe, plays a huge role in Great Britain's world-wide trade and balance of payments and is a major hub in the global shipping network.

Following the September 11 attacks in 2001 the American security authorities have already identified Southampton as one of the British ports where US customs officials will work alongside their British counterparts checking containers heading across the Atlantic for any potential terrorist connection.

Associated British Ports, owners and operators of Southampton docks, said it was company policy not to comment on any details connected with the protection of the port.

Under the security proposals, for use in times of increasing terrorist tension, now being scrutinised by the government, and other European Union member nations, every port will undergo a security assessment together with the introduction of a three-stage system of alert.

Stage one would be the normal level of security expected from all ports, level two implemented where there is definite evidence of a threat while the highest state, stage three, could see armed police or even troops on patrol together with other stringent security measures put into action, including possible involvement of the intelligence services. Ships, especially those flying overseas flags of convenience, visiting ports would be subject to rigorous inspections and additional control measures.

All these measures were discussed at a diplomatic conference, attended by representatives of more than 100 governments, held at the London headquarters of the International Maritime Organisation.