Yesterday, Ben Pile and I were having a somewhat fruitless exchange of views with Mark Johnston, who seems to be a Senior Advisor at the European Policy Centre, whatever that is. Johnston seemed to be of the view that the "No Dash for Gas" activists who had occupied EDF's West Burton gas plant were somehow justified because of global warming. He claimed that there is "a moral duty to act".
By coincidence, the US Ninth Circuit court has been considering just this argument in a case involving the Sea Shepherd, the ship that has taken it upon itself to harass and attack Japanese whaling vessels. Overturning the decision of a lower court, the judge ruled, in the following rather amusing terms, that the Sea Shepherd's actions constituted piracy:
You don’t need a peg leg or an eye patch. When you ram ships; hurl glass containers of acid; drag metal-reinforced ropes in the water to damage propellers and rudders; launch smoke bombs and flares with hooks; and point high-powered lasers at other ships, you are, without a doubt, a pirate, no matter how high-minded you believe your purpose to be.
Legal blog The Volokh Conspiracy examines the decision here, here and here, concluding that the judge's decision is "obviously correct" in law.
This is obviously an American case rather than a British one, but I imagine the precedents in these areas are not very different between the two countries, something the greens would do well to remember.