The lord chief justice, Lord Judge, said that the convictions were "unsafe because of significant non-disclosure" of secret surveillance tapes recorded by Kennedy. He said: "We have reached the clear conclusion that all these appeals against conviction will be allowed."
The campaigners left the high court in London vindicated in their belief that their original convictions had been a miscarriage of justice.
However, police and prosecutors are left facing questions over their conduct in securing the unsafe convictions. Seven inquiries have so far been launched into the prosecution of the campaigners and the infiltration of Kennedy into the ranks of the protest movement.