SPOT checks on cargo ships arriving at Britain's biggest container terminal have today been stepped up in the wake of renewed fears over a terrorist attack.

SPOT checks on cargo ships arriving at Britain's biggest container terminal have today been stepped up in the wake of renewed fears over a terrorist attack.

Felixstowe is understood to be one of several ports where extra random searches are being carried out of vessels and cargo amid fears of a plot to smuggle a "dirty bomb" into the country.

Ports are on alert following intelligence that such a bomb was en route for Britain just days ago after reports from French and Dutch intelligence sources.

Three men appeared in court in London on Monday charged with terrorist offences after being arrested ten days ago.

Neither port officials at Felixstowe or Customs officers will discuss security measures as they say this would defeat the object of having them.

But industry sources say the extra spot checks are being carried out and everyone is being urged to be extra vigilant.

The main fear is that Osama bin Laden's al Qaida group could smuggle a "dirty bomb", which uses conventional explosives to spread radioactive or germ material over a wide area, into the heart of a city.

A bomb could be sailed direct into a port such as London, Liverpool or Southampton, or delivered in a container to Felixstowe and transported by road.

One Felixstowe forwarding company manager told the Evening Star that there was greatly increased security activity on the ships and quaysides.

"No-one is panicking but everyone is being made aware of the need to be extra vigilant. There are random searches going on and everything is being checked very thoroughly," said the manager, who asked not to be named.

"With so many boxes coming through Felixstowe though it is impossible to check very many at all – it's like looking for a needle in a haystack.

"It would be so easy to smuggle a bomb in this way. Everyone knows it, but we just have to hope it never happens."

Felixstowe has been given special equipment, known as remote radiological detection devices, so all containers can be searched for bomb material.

The devices 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 United States is so worried it wants its Customs officers stationed at all major ports – in the UK and abroad – to check all US-bound cargo before it crosses the Atlantic.

Negotiations have been taking place to have officers based at Felixstowe and government ministers are understood to have given their approval.

However, the European Commission is now threatening to take legal action against the UK if its signs the agreement with USA because it says there should be one agreement covering all the European ports.

It is already taking to court France, Belgium, Holland, Germany and Italy – which have all signed deals with the US – because it says the arrangement will give their ports an unfair competitive advantage for US trade.