An animal rights campaigner from Northampton has insisted he had nothing to do with a plot to firebomb a lab at Oxford University.
Mel Broughton, of Semilong Road, has taken the stand at Oxford Crown Court to claim he was the target of a police campaign because he was a high-profile activist against the experimental laboratory.
Broughton, 48, denies conspiracy to commit arson, possession of an article to damage property and keeping explosive substances in relation to failed firebomb attacks.
David Bentley, defending, revealed a recording of police officers discussing Broughton in 2007.
He said: "Included in that were a couple of officers who were talking about you (Broughton) in a disparaging fashion, who were discussing candidly ways to, as it were, 'get you' in some way or another.
"One was recorded as saying that he would wage a 'dirty war'."
Broughton told the court that whenever he went to Oxford, his every move was recorded by a police officer, from joining a protest to sitting in a coffee shop.
He admitted he had previously been part of a firebomb plot but added he was now too old, too high-profile and no longer willing to take part in direct action.
But forensic experts allegedly found Broughton's DNA on a bottle top and a match found at the lab.
Prosecutor John Price said when police raided the defendant's home, they found sparklers – which can be used as fuses on explosive devices – hidden in his bathroom.
Broughton said: "I have not knowingly been involved with anything to do with these devices.
"It (direct action) is something I'm no longer willing to do... I'm getting older and I'm no longer able or willing to do that."
He explained the hidden sparklers by saying he had bought them as an eye-catching addition for a night-time vigil outside the controversial lab, and added the intensive police surveillance and his criminal record had made him paranoid and caused him to conceal them.
The trial continues.