The High Court is expected to decide today if the judicial review will go ahead.
Gaunt, who was sacked from radio station TalkSPORT in 2008 for calling councillor Michael Stark an "ignorant pig" and "health nazi" in a live interview about children in care, believes Ofcom infringed his right to freedom of speech under Article 10 of the Human Rights Convention.
His lawyers include Gavin Millar QC, Mark Henderson and his solicitor, Martin Howe, who recently won the Gurkha human rights cases along with Joanna Lumley.
Liberty director Shami Chakrabarti, will argue that his fundamental right to free speech and to criticise a professional politician has been infringed by Ofcom's ruling.
Gaunt, who was himself in care as a child, was censured by broadcasting regulator Ofcom in May 2009 for a "bullying" and offensive interview.
Ofcom said today that its decision was "independent of and subsequent to any decision in relation to Jon Gaunt's employment by TalkSPORT".
[The interview can be found on YouTube at this link]
Gaunt's solicitor says that Ofcom refused to disclose details of the 53 complaints under the Freedom of Information Act, and that Michael Stark himself never complained.
"I don't see why in the 21st century in one of the greatest democracies in the world, an unelected quango like Ofcom can say what's offensive and what's not offensive," Gaunt told Journalism.co.uk, ahead of the afternoon hearing.
They have "no right to stifle open and robust debate," he said.
"I don't think there's a need for Ofcom whatsoever," Gaunt added. "If I have to lose my job speaking out for 60,000 children in residential care, then so be it."
Gaunt told Journalism.co.uk he will fight the human rights case first, before turning his attention to suing TalkSPORT.
"It started off about me, and TalkSPORT, and TalkSPORT being wrong to sack me, which I still believe they are."
"I will pursue TalkSPORT; I will pursue them like a rabid dog, but first I'm pursuing the right for all broadcasters - even people like George Galloway - whose views I can't stand.
"We have a right to express ourselves without fear of censorship from an unelected quango."
His solicitor Martin Howe said that fighting this case was important for British democracy.
Human rights legislation was, he said, the "nearest thing we have to a written constitution.
"This is a very serious and constitutional case. We are the longest unbroken democracy in the world and right to free speech has been there since the days of the Magna Carta, since the beginning."
But Ofcom argues its decision did not infringe freedom of expression: "In reaching its decision that Jon Gaunt went too far in this particular broadcast with his offensive language and bullying style, Ofcom took into account all relevant factors including the context of the interview, Jon Gaunt's robust style and of course the principles of free speech," the regulator stated today.
"Ofcom's role is to decide whether a particular broadcast is in breach of generally accepted standards in the Broadcasting Code.
"In this particular broadcast, Ofcom decided that Jon Gaunt went too far with offensive language and a bullying style."
An inital written application for judicial review was refused permission in December 2009. In court documents for the renewed oral application, Gaunt's lawyers argue this was in "error" and Ofcom's QC states the decision was "correct".
Also on Journalism.co.uk:
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