Boats from Pembrokeshire have joined a flotilla assembling off the north Wales coast to protest against a shipment of radioactive fuel expected to pass through the Irish sea.

A 150-ton supply vessel has left Porthgain to join the flotilla which is mounting a 'symbolic' protest led by environmental campaigners Greenpeace's flagship Rainbow Warrior off Holyhead.

The Sea Empress disaster was bad enough but you can clean up oil - you can't see or clean up radioactivity

Andrew Clemence, Pembrokeshire Anti-Nuclear Alliance

The armed shipment is en-route from Japan to Barrow in Cumbria as part of a purpose-built fleet carrying more than 200 kilos of mixed oxide nuclear fuel destined for British Nuclear Fuels Ltd (BNFL) at the Sellafield reprocessing plant.

A yacht and rigid inflatable boat have also left Fishguard to join the Welsh protest which is being co-ordinated by Pembrokeshire vet Andrew Clemence.

Mr Clemence is chairman of Pembrokeshire Anti-Nuclear Alliance and warns there could be ecological catastrophe if something goes wrong with the convoy.

"It's 90% certain the shipment will pass our coastline.

"There's strong feeling down here about it - most people don't know that it goes on," he said.

"The aim of this protest is to highlight the fact that it does and to try to get the powers-that-be to stop it from happening.

"If one of these ships went aground or caught fire it's unbelievable to think what would happen.

"The Sea Empress disaster was bad enough but you can clean up oil - you can't see or clean up radioactivity.

"The seas around here would be affected for thousands of years so the tourism and fishing industries would be totally wiped out."

The cargo has been sent back from Takahama in Japan after safety records at Sellafield, which is operated by BNFL, were exposed as false in 1999.

Up to 20 vessels are due to assemble in Holyhead for the protest, which could take place late on Sunday or early next week.

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

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 renegades.

On Tuesday, Greenpeace confirmed the location of the two plutonium ships, the Pacific Pintail and Teal, off the west coast of Madeira, in international waters.

The vessels have already faced protests by a 50-strong flotilla in the Tasman Sea between Australia and New Zealand after setting out from Japan on 4 July.