The campaigners painted the name "Gordon" on the chimney
The six Greenpeace activists who caused £30,000 of damage to a power station are not the first to be acquitted in court of criminal charges relating to protests.
Previous environmentalists and anti-war campaigners have been cleared after admitting to carrying out a wrecking spree during direct action.
In the latest incident, activists scaled a chimney at Kingsnorth power station in Hoo, Kent in October 2007 in protest against plans to build a new coal-fired plant on the site.
Judge David Caddick told the jurors at Maidstone Crown Court the country had a history of "accommodating protests" but it did not extend to breaking the law.
But the protesters claimed they were lawfully right to damage the plant because they believed it would prevent further harm around the world from global warming.
The proposed new power station would be the first in the UK built to use coal in 30 years.
A few other notable cases have had similar results for campaigners charged with breaking the law during protests.
In September 2000, a jury found former Greenpeace executive director Lord Peter Melchett and 27 environmental activists not guilty of causing criminal damage following their protest against GM crop trials.
The defendants had admitted destroying a six-and-a-half acre field of genetically modified maize in July 1999, Norwich Crown Court heard during a two-week trial.
A sheriff ruled naval base weapons were illegal under international law
The campaign group which destroyed the crop said they were acting to prevent neighbouring property - organic crops and gardens - being damaged by genetically modified pollen.
They were previously cleared of stealing the genetically modified maize by a different jury.
Peace activists have also had courts rule in their favour. In January 2001, two anti-nuclear activists who admitted plotting to disarm one of Britain's Trident submarine fleet were cleared.
'Upholding international law'
In that case, the jury at Manchester Crown Court found Sylvia Boyes and Keith Wright, an Open University lecturer who changed his name to "River", not guilty of conspiracy to cause criminal damage to HMS Vengeance.
They entered the Marconi shipyard at Barrow-in-Furness, Cumbria, in November 1999, armed with hammers and other tools in an attempt to damage the nuclear-powered submarine.
The jury accepted the defendants' claim that as they were upholding international law they themselves were not committing an offence.
Toby Olditch and Philip Pritchard wanted to stop the Iraq war
In Scotland, three anti-nuclear activists from the Campaign for Nuclear Disarmament (CND) were acquitted of maliciously damaging a naval base when the Sheriff said the weapons were illegal under international law.
The three women, Angela Zelter, 48, Ellen Moxley, 45, and Bodil Ulla Roder, 45, had damaged a barge and laboratory equipment at the Faslane Naval Base near Lochgoilhead, Argyll in June 1999.
During their four-and-a-half week trial they had argued that a ruling by the International Court of Justice in 1996 made Trident and all nuclear weapons illegal.
Similarly, in May 2007, Toby Olditch, and Philip Pritchard, were cleared of conspiring to cause criminal damage at RAF Fairford, Gloucestershire.
The activists, from Oxford, admitted using bolt cutters to cut through a perimeter fence and trying to sabotage B-52 bombers prior to the start of the Iraq war, but said they were trying to prevent war crimes.