GREENPEACE activists have staged a protest aimed at blocking a ship carrying oil from the Arctic, where a confrontation last year led to the arrest of 30 people.
Two of the so-called Arctic 30 - Phil Ball from Oxford, and American Pete Willcox - were among a group of protesters who took action in the port at Rotterdam.
The environmental group said yesterday's action was against a Gazprom tanker carrying the first oil from Arctic waters.
Around 30 of the 80 activists were arrested during the demonstration, which involved Greenpeace's flagship Rainbow Warrior.
Activist Faiza Oulahsen from the Netherlands, said: "Thirty of us went to prison for shining a light on this dangerous Arctic oil, and we refuse to be intimidated. This tanker is the first sign of a reckless new push to exploit the Arctic, a place of incredible beauty which is melting before our eyes."
Greenpeace International Executive director Kumi Naidoo said: "It's increasingly clear our reliance on oil and gas is a major threat not just to the environment, but to global security.
"Arctic oil represents a dangerous new form of dependence on Russia's state owned energy giants at the moment when we should be breaking free of their influence. We cannot hope for any kind of ethical foreign policy while our governments remain hopelessly dependent on companies like BP, Shell and Gazprom."
Greenpeace said its Save the Arctic campaign has collected over five million signatures including faith leaders and Nobel peace prize winners.