At least two other oil slicks have been appeared in the sea near the site of the Sea Empress spill, raising fears that other ships may be using the disaster to dump oil deliberately.
The Royal Society for the Protection of Birds yesterday said that oiled birds were being picked up in Rhyl, north Wales, too far away to have been affected by the Sea Empress. There has also been a spill on the North Devon coast which appears not to have come from the Empress.
Members of the RSPB monitoring scheme had also seen a slick on the Merioneth coast in north-west Wales, and another in Carmarthen Bay, site of the initial problem, neither of which were from the Empress.
Chris Harbard, spokesman for the RSPB, said yesterday: "We have picked up several common scoters near Rhyl and on the North Devon coast birds have been in oil which appears different from that of the Empress." He said that ships coming to Britain were supposed to clear their oily bilges in port but that it was cheaper and quicker for them to do so while at sea. "This happens more often in the winter when the nights are longer because the ships do it under cover of darkness."
The Marine Control Pollution Unit confirmed the existence of at least two other slicks, but was unable to confirm their origin. A spokesman said: "We have no evidence that masters are discharging oil illegally on purpose."
Meanwhile, Tony Blair, the Labour leader, on a St David's Day visit to Wales to talk about plans for a Welsh Assembly, joined the Pembroke MP Nick Ainger to meet teams involved in the clean-up operation.
At the RSPCA emergency hospital in Milford Haven he was shown oiled seabirds being fed and washed. So far more than 2,600 have been recovered but 1,500 have died.
Mr Blair said: "It is absolutely essential that we take steps to ensure that this never happens again".
He said that recommendations made by Lord Donaldson in the wake of the Braer spill had not been implemented by the government.
Animal welfare groups involved in rescue operations will be able to claim compensation from the ship's insurers, the Government said last night.Reuse content