The trial of the six Greenpeace UK activists was the first case in which acting to prevent climate change causing damage to property formed part of a 'lawful excuse' defence

This article is more than 12 years old

This article is more than 12 years old

Six Greenpeace climate change activists have been cleared of causing criminal damage at a coal-fired power station in a verdict that is expected to embarrass the government and strengthen the anti-coal movement.

The jury of nine men and three women at Maidstone crown court cleared the six, five of whom had scaled a 200m tall chimney at Kingsnorth power station at Hoo, Kent in October 2007.

Greenpeace activists on the painted chimney. Photograph: Will Rose/Greenpeace

The activists admitted trying to shut down the station by occupying the smokestack and painting the world "Gordon" down the chimney, but argued that they were legally justified because they were trying to prevent climate change causing greater damage to property around the world.

It was the first case where preventing property damage caused by climate change has been used as part of a "lawful excuse" defence in court. It is now expected to be used widely by environment groups.

The court had heard from Prof James Hansen, one of the world's leading climate scientists, that the 20,000 tonnes of carbon dioxide emitted daily by Kingsnorth could be responsible for the extinction of up to 400 species.

Hansen, a Nasa director who advises Al Gore, told the court that humanity was in "grave peril".

He said: "Somebody needs to step forward and say there has to be a moratorium, draw a line in the sand and say no more coal-fired power stations."

It also heard David Cameron's environment adviser, millionaire environmentalist Zac Goldsmith, and an Inuit leader from Greenland say that climate change was already seriously affecting life around the world.

The court was told was that some of the property in immediate need of protection included parts of Kent at risk from rising sea levels, the Pacific island state of Tuvalu and areas of Greenland.

The defendants also cited the Arctic ice sheet, China's Yellow river region, the Larsen B ice shelf in Antarctica, coastal areas of Bangladesh and the city of New Orleans.

Goldsmith told the court: "By building a coal-power plant in this country, it makes it very much harder in exerting pressure on countries like China and India to reduce their burgeoning use of the fossil fuel."

The jury was told that Kingsnorth emits the same amount of CO2 as the 30 least polluting countries in the world combined – and that there are advanced plans to build a new coal-fired power station next to the existing site on the Hoo Peninsula in Kent.

Greenpeace used the court's decision to pile pressure on government to abandon plans for a new generation of coal-fired plants.

"Today's acquittal is a potent challenge to the government's plans for new coal-fired stations from jurors representing ordinary people in Britain who, after hearing the evidence, supported the right to take direct action in order to protect the climate," said Ben Stewart, Greenpeace's communications director who was one of the six acquitted.

The others were Will Rose, Kevin Drake, Tim Hewke, Huw Williams and Emily Hall.

"It wasn't only us in the dock, it was coal-fired power generation as well. The only people left in Britain who think new coal is a good idea are business secretary John Hutton and the energy minister Malcolm Wicks," said Hall.

"It's time the prime minister stepped in and embraced a clean energy future for Britain."