Roger Pearce was a member of the police’s top secret Special Demonstration Squad [SDS]

A SPY cop’s report about a plot to blow up North London Line trains transporting nuclear waste was an absurd fantasy used to justify a top secret undercover unit’s existence, an inquiry has heard.

An officer who infiltrated the “anarchist movement” in the early 1980s claimed “people against the nuclear programme built a bomb” that was “actually found” on the overground railway that runs through Islington.

The route goes through Highbury and Islington station and has recently been renamed the Mildmay Line by London Mayor Sadiq Khan.

The explosive claims from Roger Pearce, known to the inquiry as officer HN85, are discredited by several activists in statements published by the Undercover Policing Inquiry for the first time this week.

The statements tell how for many years nuclear waste was transported on the line from power stations in Kent, Suffolk and Essex to Sellafield, Cumbria.

The documents show how peace groups feared a terrorist attack on the trains could cause a national emergency and considered planting a fake bomb on the network for publicity.

The witness statement from Michael Zeitlin, a campaigner for the anti-nuclear movement, said: “I firmly believe that HN85 has deliberately suggested that a real bomb was planted in order to elevate the status of his reports and so justify his spying.

“I am convinced that any possible ‘bomb on the North London Line’ refers to informal discussions of placing a fake bomb as a publicity stunt, in order to draw attention to the threat created by the transportation of nuclear waste through residential areas.

“The idea that an actual bomb would have been planted is patently absurd as the whole issue was one of public safety. Such a bomb plot does sounds very much like fiction as might be found in a novel.”

The documentss show how a meeting of the Hampstead CND branch had heard discussions about “some form of action to protest against the transportation of nuclear fuel” but this had been “completely taken out of context and then grossly exaggerated” by the undercover officer.

Mr Pearce’s statement to the inquiry said: “There were people who were prepared to take violent action against the nuclear policy of the UK and I felt this provided justification for reporting on them.

“People against the nuclear programme, including anarchists who were my associates, built a bomb on the North London Line which transport nuclear waste.”

The inquiry docs show how Roger Pearce – there is no reporting restriction on using his name – trained as an Anglican Priest at Durham before joining the police in 1973.

He joined the Special Demonstration Squad that was set up by the Met to “prevent violent disorder” but led to officers spying on dozens of left-wing organisations and pacifist groups over four decades with little to no gain.

Training for the “top secret unit” took place at Holborn police station, Mr Pearce’s witness statement reveals, while recruitment took place on a “tap on the shoulder in the corridor” basis.

He chose the “legend” Adrian Roger Thorley, a name taken from a child who was killed in a road accident in in Stoke on Trent, and lied about being a van driver delivering spare parts for the car company Ford.

He lived in a “cover flat” off the Goldhawk Road in west London and wore red and black with shoes with “worn through soles”, claiming he was given the prestigious nickname “Trotsky” by activists he was spying on.

“Using a deceased child’s identity was a distasteful practice and a violation of privacy but we felt it would never be revealed,” his statement said.

The UCP Inquiry was launched in 2017 after it was revealed that some SDS officers used names of dead children and fathered children with activists.

Huge resources were ploughed into the discredited project with critics saying the ends did not justify the means.

More than one million documents have been submitted to the inquiry –already the longest and most expensive in British history – that is not expected to conclude until 2026.