SECURITY is set to be stepped up at Felixstowe port amid growing fears that terrorists will use it to smuggle weapons into Britain.The news revealed today comes just weeks after the discovery of a cache of mortar shells, guns, and Semtex explosive at the port.

SECURITY is set to be stepped up at Felixstowe port amid growing fears that terrorists will use it to smuggle weapons into Britain.

The news revealed today comes just weeks after the discovery of a cache of mortar shells, guns, and Semtex explosive at the port.

Anti-terrorist officers are remaining tight-lipped over the find and have thrown a veil of secrecy around their investigations into those responsible.

Sources in Suffolk say the investigation was moved swiftly to London and no further information has been given out – except to rule out any further Felixstowe link in the chain leading to the smugglers.

The haul of weapons found inside a car in a container included hand guns, hand machine guns, detonators, Semtex, and mortars which were designed to kill and maim large numbers of people.

Officers have refused to disclose who they believe the weapons were destined for – though it is believed to be more likely to be terrorist groups such as the Real IRA or Osama bin Laden's al Qaida than London gangland organisations.

The International Maritime Organisation met last week to discuss worldwide port security in the wake of the September 11 atrocities in New York.

The IMO agreed a series of measures to step up security, including the use of security officers aboard all ships and in ports, and for new laws requiring ports to provide security plans, including assessment of their vulnerability to attack.

It was also agreed to look at ID for seafarers and new ways for examination of container cargo.

Felixstowe has already been identified as one of several British ports to have devices which can spot radioactive material installed following September 11. The equipment known as remote radiological detection devices can seek out traces of plutonium or enriched uranium and can either be hand held or attached to a static object such as a security barrier.

The scanners aim to stop bin Laden smuggling a "dirty bomb" – a weapon which uses conventional explosives to spread radioactive material over a wide area to cause huge long term health risks or make areas uninhabitable.

Following the discovery of the weapons in a car at Felixstowe, a man and a woman, both white and of UK origin, were arrested.

They were held in custody at a central London police station for 21 hours after being arrested under the Terrorism Act 2000, but released without charge.

The car was in a box unloaded at Trinity Terminal from a ship which had last called at Holland, although details of its previous destinations are not known.

Customs and Excise officers who discovered the consignment in a routine inspection immediately sealed off part of the port and called the 621 Squadron bomb squad as a precaution and to ensure the weapons were made safe.

A New Scotland Yard spokesman said there had been no further arrests and there would be no additional information released about the weapons or the progress of the investigation.

One source at Felixstowe said: "The anti-terrorist people took everything away the day after the weapons were found – and they have never been back.

"We were all told not to say a word, but everything we knew has been in the newspapers anyway and we have not been told anything further. It is very intriguing all the same."