Cook Report presenter Roger Cook had "never heard" of a former child actor who falsely claims he was molested by former Chancellor Kenneth Clarke while working on the show in 1994, a court was told.
Ben Fellows, 40, from Birmingham, alleged that the heavyweight politician had plied him with alcohol and carried out the sexual assault in the office of political lobbyist Ian Greer during a cash-for-questions sting operation.
In the autumn of 2012, he told national news reporters about the alleged assault and stories were published in print and online, jurors at the Old Bailey were told.
He went on to make a statement to police after being interviewed by officers as part of Operation Fairbank - the high profile investigation into Westminster historic child sex abuse.
In it he claimed he had been assaulted while working as an undercover actor for ITV's Cook Report.
He added that there were a number of people who had also worked on the show at the time and were aware of the assault.
But giving evidence today, Mr Cook, who presented the programme and had some editorial control, said he had never heard of Fellows, or the allegations he is accused of fabricating.
When asked what, if any, dealings he had with the defendant, Mr Cook replied: "None whatsoever. He first came to my notice when the programme manager rang me up and said 'have you seen this blog?'.
"It was a blog from Mr Fellows claiming that he used to work for the Cook Report from 1990. I had never heard of him."
He added that he would have known if Fellows worked on the show.
Jurors were told that Mr Cook only became aware of the allegations against Mr Clarke after that particular show was cancelled.
Prosecutor Duncan Atkinson asked the witness what he knew of the "Clarke allegations" in the 1990s - when the politician was Chancellor of the Exchequer.
Mr Cook replied: "Nothing. After the programme was over there was no conversation about it at all."
He added: "That would be a substantial story. And probably not us, but somebody would have run with it.
"It would have been an enormous story, if that allegation was made."
The court has heard how police interviewed members of the Cook Report team who said they were all unaware of the allegation.
When officers checked out Fellows's version of events, they concluded they were false and began treating him as a suspect rather than a victim, the court heard.
After Fellows was arrested, he insisted the allegations were true, saying the Cook Report staff were too afraid of losing their jobs or "falling foul of the establishment" to corroborate them.
He also claimed he was subject to intimidation and threats as a result of having spoken out.
Jurors have heard that in 2012 Fellows also claimed he had been abused by a number of people in the entertainment industry, including a senior female executive at the BBC whom he claimed seduced him when he was aged between 14 and 16.
He alleged that he been invited to a cocaine-fuelled party on BBC premises hosted by two of Britain's biggest stars of the day, the court heard.
The defendant, of Redstone Farm Road, Olton, Solihull, denies perverting the course of justice between November 14 2012 and December 1 2012.