A flotilla of ships led by the Greenpeace flagship Rainbow Warrior has left north Wales on its way to intercept two ships carrying nuclear fuel through the Irish Sea.

Vessels left the port early on Sunday morning to make their way into the Irish Sea to protest against the transport of the material from Japan to the nuclear plant at Sellafield in Cumbria.

Some of the boats will patrol the southern part of the sea, while others will be deployed near the port of Barrow-in-Furness, where the two nuclear transport ships will dock.

The transport could go round Ireland or past Wales

Protestors are expecting the ships - the Pacific Pintail and Teal - to arrive some time in the next few days, but are not certain whether they will sail past Wales or take the route around the west of Ireland.

One of the protestors is Des Llewellyn from Pembrokeshire, who is sailing on the Elkstone, one of about 20 boats in the flotilla.

He said: "This shipment poses a huge security threat to the Irish Sea. There is now more chance of an attack on a nuclear facilty of vessel since September 11.

"The UK government are making it easier for terrorists to make that attack by shipping nuclear material around the world."

Irish pop star Jim Corr, from the group The Corrs, is one of the protestors onboard the Rainbow Warrior.

Pop star Jim Corr is one of the protestors

He said: "Our intention is to convey the message that our oceans must not be used a method of transporting hazardous nuclear material and the Irish Sea should never be used as a nuclear highway ever again."

The ships are part of a purpose-built fleet on a voyage carrying more than 200 kilos of mixed oxide nuclear fuel destined for British Nuclear Fuels Ltd (BNFL) at the Sellafield reprocessing plant.

The cargo of fuel, which came from Sellafield originally, has been sent back from Takahama in Japan after safety records at the plant operated by BNFL were exposed as false in 1999 .

BNFL called on the protestors to ensure that the flotilla did not endanger the ships' journeys.

But Greenpeace campaigners said they do not plan to interfere with the vessels' safe navigation.

The ships will need a high tide in order to reach the port of Barrow in Cumbria, but BNFL is not giving any details of their itinerary for security reasons.

Use of fuel disputed

Greenpeace claims the ships are carrying enough plutonium waste to make 50 nuclear bombs, which make them a potential target for terrorists.

BNFL denies this claim, insisting its cargo includes low-grade plutonium which would be of no use to terrorists.

Mixed-oxide fuel is made by reprocessing spent uranium fuel rods from nuclear plants.

The Sellafield plant separates the rods' plutonium radioactive waste from the remaining unused uranium.

Recycled uranium and plutonium is made into ceramic pellets which can be used again in a nuclear power plant.

BNFL said one fingernail-sized pellet could generate as much energy as a ton of coal.