London mayoral candidate Laurence Fox is being sued for libel after he called three people "paedophiles" on Twitter.
Mental health campaigner Simon Blake, Drag star Crystal, and actress Nicola Thorp began legal proceedings against actor-turned-activist on 1 April.
The claimants allege Mr Fox defamed them on Twitter in October. The comments have since been deleted.
Mr Fox defended his comments, claiming the term "paedophiles" was a "meaningless and baseless" insult.
During the manifesto launch for the Reclaim party, which Mr Fox leads, he said he was unaware of the defamation case.
Mr Fox said: "Free speech. You throw meaningless and baseless insults at someone you get a meaningless and baseless insult in return."
He added: "People can call me whatever they want."
The comments followed a tweet from the supermarket Sainsbury's, which shared its support for Black History Month.
On 4 October, Mr Fox tweeted that Sainsbury's marking Black History Month "promoted racial segregation and discrimination".
He called for people to boycott the supermarket.
In response, Mr Fox claims he was "called a racist."
Mr Fox called both Mr Blake and the former RuPaul's Drag Race contestant, whose real name is Colin Munro Seymour, "paedophiles".
At the time, Crystal said: "An accusation of paedophilia is one of the oldest homophobic tropes, and it was very shocking to have that levelled at me, not just by Mr Fox, but also his many followers who believed him.
"I may have had to endure homophobic bullying as a child, but I will not tolerate it as an adult."
Following the legal action, Crystal said "it would be inappropriate to comment further".
He used the same label against Ms Thorp in a different thread.
Mr Blake and Ms Thorp have both been approached for comment.
Law firm Patron Law has filed a claim on behalf of the trio in the High Court.