Full details of a plot by climate change activists to shut down a Nottinghamshire power station have emerged.
The protesters planned to disable Ratcliffe-on-Soar's plant for a week in 2009 by climbing the chimney and chaining themselves to conveyor belts.
They said they intended to starve the coal-fired station of fuel.
A tip-off by undercover policeman Mark Kennedy, who infiltrated the group, led to the arrest of more than 100 people.
But Kennedy later switched sides, leading to the quashing of convictions against 20 of the protesters.
In an interview for BBC's Inside Out, detectives and campaigners have spoken about the raid at Iona School in Sneinton - located about 10 miles from the power station - which led to the arrest of 114 people.
The police seized thousands of items in the raid, including climbing ropes, metal grinders, chains, locks, pre-packed meals and a steel barrier.
Protester Sarah Shoraka, 33, of Stoke Newington, north London, said their aim was to take direct action to stop carbon emissions.
"I was going to climb up the chimney and… the idea was to starve the power station of fuel by occupying the conveyor belts," she said.
"I had no idea that this sort of thing could happen… and that there would be a police spy... it sounded like something from a novel or a film."
Protester Dan Glass, 27, of Glasgow, said: "The idea was to shut the power station for up to a week and there was enough food and water to enable that.
"Some people would have been on top of the power station and some people would have been locked on to other places."
Nottinghamshire Police said they had "struck early to protect the critical national infrastructure".
The action had "minimised any risk of injury or harm to the protesters... and stopped any damage being caused and any of the staff at the power station or my officers being injured", according to Supt Paul Anderson.
A national review of undercover policing was started as a result of the role in the arrests of Mr Kennedy, who worked for the Metropolitan Police but has since left the force
The Independent Police Complaints Commission (IPCC) is investigating whether Nottinghamshire Police disclosed all relevant material to prosecutors in the case and the Crown Prosecution Service is examining whether evidence was kept from defence lawyers.
Mr Kennedy, who used the name Mark Stone in his covert work, spent seven years working undercover in the green movement across Europe.
Power Struggle, an Inside Out Special, will air on BBC1 in the East Midlands region from 19:30 BST on 10 October.