Broadcaster Jon Gaunt, who called an interviewee a "Nazi" on air, lost an appeal today against a High Court ruling that media watchdog Ofcom was justified in upholding complaints against him.
Gaunt's contract was terminated by TalkSport in November 2008, 10 days after an exchange with councillor Michael Stark.
During a hearing last month, the Court of Appeal was told that Gaunt's live interview with Mr Stark about Redbridge Council's decision to ban smokers from becoming foster parents - for which he later apologised - drew 53 complaints from listeners.
Mr Stark said the welfare of children should outweigh the needs of foster families but Gaunt, who was himself in care, accused the councillor of being a "Nazi", a "health Nazi" and an "ignorant pig".
Last summer, Gaunt challenged Ofcom's June 2009 finding that the interview failed to comply with the broadcasting code but the High Court backed Ofcom.
Three Court of Appeal judges today rejected his appeal against the High Court's decision.
Giving the ruling of the court, the Master of the Rolls, Lord Neuberger, said: "Freedom of expression - that is, the right to say what one wants and how one wants, and to impart and to receive information and ideas - is a fundamental human right.
"In the light of the power of language, ideas and information, freedom of expression underpins a free society."
Lord Neuberger, who heard the case with Lords Justices Toulson and Etherton, said freedom of expression had been described as "the lifeblood of democracy".
But he added: "However, like virtually all human rights, freedom of expression carries with it responsibilities which themselves reflect the power of words, whether spoken or written.
"Hence the need for some restrictions on freedom of expression..."
The need for some restrictions was recognised by Article 10 of the European Convention on Human Rights, in which freedom of expression was now "enshrined".
As the "limited number" of circumstances for restriction identified in that Article recognised "any attempt to curtail freedom of expression must be approached with circumspection".
Ofcom's finding in relation to the Gaunt interview "was essentially based on the proposition that it caused significant and unnecessary offence".