Military experts say there is a real possibility that the vessels could be targeted by terrorist groups or rogue states intent on acquiring nuclear weapons. They say the guns mounted on the ships are inadequate to fend off a well orchestrated attack by pirates with superior weapons.
Janes, the internationally renowned arms and naval authority, agrees. "It would not take much fire-power to knock them out," it said. The ships were "capable of repelling only a lightly armed attack" and should be protected by "at least one well-armed frigate".
The shipment, which will take place in the next few months, is planned as the first of many over the next year. The number will increase sharply if ministers allow a new plutonium plant at Sellafield, the controversial Cumbrian complex, to start up. The plutonium, for power stations, is extracted from spent Japanese fuel which is reprocessed at Sellafield and at Cap la Hague, France.
The prospect of such shipments has long worried security experts. Eleven years ago the US defence department said they would be "accessible and vulnerable throughout the voyage, particularly when the vessel is passing through channels, straits, and other restricted waterways, or when it is near the coast".
The last plutonium shipment from Europe to Japan, in 1992, was accompanied by a specially built patrol boat operated by the Japanese Maritime Security Agency. The US, which provided the original nuclear fuel to Japan and, under a special agreement, has to approve security arrangements for shipments of plutonium extracted from it, has repeatedly promised that all of them would be accompanied by "an armed escort vessel".
But it is now clear that the new shipment will not be protected by a warship. Britain, France and Japan all refuse to give details of the route or the security arrangements and will only name the ships, describe what they are carrying, and say when they are setting out, "only on one or two days before departure from Europe".
US government documents show that the two freighters - the Pacific Teal and the Pacific Pintail - will each carry three 30mm guns and will be staffed by officers of the United Kingdom Atomic Energy Authority armed with "assault rifles, shotguns and hand weapons".
Paul Leventhal, director of Washington's Nuclear Control Institute, said: "Two freighters riding shotgun for each other will not repel a real-world attack."
Dr Fr ank Barnaby, former director of Stockholm Peace Research Institute, said maritime hijackings were "becoming more frequent and violent" - there were 66 in the first three months of this year - and added: "The attacks are generally made at night using speedboats. This should give those responsible for the security of nuclear cargoes pause for thought."
Many studies have shown that a terrorist group, let alone a rogue state, could get the plutonium from the fuel and make it into nuclear weapons.
The US has approved the scaled-down security because, critics say, it does not want to antagonise France, Britain and Japan. It says the freighters count as armed escort vessels because the shipments are being carried out "on government service" by British Nuclear Fuels (BNFL), a nationalised industry.
Critics say security has been lessened partly to save money and partly as a public relations exercise because using a warship escort would demonstrate vividly how dangerous the cargo is. Martin Foreward, campaign co-ordinator of Cumbrians Opposed to a Radioactive Environment, who has been monitoring the arming of the freighters at Barrow-in-Furness, said: "Once again BNFL is taking the cheap option, but this time it is putting not just Cumbria but the whole world at risk."
A meeting of Prime Ministers of Eastern Caribbean states, on one of the possible routes, called on Britain, France and Japan "to stop these shipments forthwith".
BNFL said its priority was "doing a good job and doing it safely".Reuse content