Tommy Robinson has told the High Court he secretly recorded conversations with school staff to gather evidence for his libel trial.
The English Defence League founder is being sued by Jamal Hijazi, who was filmed as he was attacked in a school playground in Huddersfield.
Mr Robinson, whose real name is Stephen Yaxley-Lennon, made disputed claims about Mr Hijazi in two Facebook videos.
Mr Robinson is relying on a defence of truth in the libel action.
He had said the Syrian refugee, who was a 16-year-old student at Almondbury School when the footage was filmed, "violently attacks young English girls in his school", "beat a girl black and blue" and had threatened to stab another boy at his school.
He told a preliminary hearing at the Royal Courts of Justice he felt it necessary to secretly record some of his conversations with school staff.
"If people were free to tell the truth, I wouldn't be standing here," he told Mr Justice Nicklin.
He said the conversations involved people who had "good jobs," but were "scared to stand by" him.
Judge Nicklin said: "These people, I suspect, will be shocked to find they have been secretly recorded and are now featuring in a High Court libel trial."
Mr Robinson said he needed to prove to people what they had said to him and because "the media are about to tell people I lied, that I made it up, but I need people to know I told the truth."
He was not legally represented in court after telling an earlier hearing he "could not afford" a lawyer.
The trial is due to begin on 19 April. The pre-trial hearing was adjourned until then.