Louise Edge, a spokeswoman for Greenpeace on board the Esperanza, insisted that campaigners had only boarded one Scottish vessel at the weekend after receiving the consent of the skipper. The discussions, she said, had been "extremely amicable".

She denied that any threats had been made. She said: "We did say that we were out here to protect the area and that we would like them to consider leaving the area. "Obviously we are a direct action organisation and the chance of taking direct action is always there."