Caroline Lucas, the only member of the British Parliament from the Green Party, and four other activists were found not guilty of obstructing a public highway and public order during a protest against hydraulic fracturing last year in Balcombe, a village in West Sussex.
Brenda Pollack, a Friends of Earth campaigner, said the controversial drilling practice dubbed fracking should be on trial, not its opponents.
"Fracking is a risk we cannot afford to take -- it's bad for the planet, will not lower our energy bills and will leave generations to come in a mess they can’t sort out," she said in a statement Thursday.
The British government is looking to replicate the U.S. success with shale natural gas, though the program is in its infancy.
British shale explorer Cuadrilla Resources last year was the target of major protests after it started exploratory drilling in Balcombe. Protesters were concerned the drilling campaign was a prelude to a hydraulic fracturing operation, though the process was not conducted at the site.
Lucas, in a statement posted on her Twitter account, said the court ruling was a "victory for whole movement against dirty fracking and for cleaner energy."