British radio presenter Jon Gaunt has lost a legal challenge after he branded an interview guest a "Nazi". But is language like that ever acceptable?

Gaunt was interviewing Redbridge councillor Michael Stark about the London borough's plans to ban smokers from fostering children when he labelled him a "Nazi", a "health Nazi" and an "ignorant pig".

Some 53 people complained to the media regulator Ofcom about his language during the November 2008 interview on Talksport and Gaunt was subsequently sacked.

Now the High Court has backed up Ofcom's ruling, saying it did not breach the presenter's right to free speech.

But while Gaunt's line of argument might have been unacceptable for the public airwaves, it would have been utterly unremarkable in many corners of the internet.

That's because Gaunt's diatribe characterises an extension of Godwin's Law - a rule that, over time, all internet debates will end up with one participant comparing another to Adolf Hitler, or the Nazis.

Godwin's Law As an online discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches 1 Mike Godwin 'Nazi' jibe radio host loses bid

Its author, US lawyer Mike Godwin, created his theory in 1990 after observing participants in Usenet newsgroups - early online discussion forums - hoping to make people think before they posted.

Comments like Gaunt's, he says, are all-too familiar.

"No-one can justify calling someone a Nazi simply because their views differ on matters of healthcare policy," he says. "When you get these glib comparisons you lose perspective on what made the Nazis and the Holocaust particularly terrible."

Despite this, Mr Godwin - who now works as general counsel to the Wikimedia Foundation - believes there is no need for regulators to get involved when people use offensive language.

Comparing someone to Hitler has become an internet faux pas, he points out, with fellow users quickly citing Godwin's Law in response to offending posts.

However, he says there has been a worrying decline in standards in the wider world.

Image caption Mike Godwin says his internet law can be observed in the wider world

Through the 1990s and into the 21st Century, use of terms such as "feminazi" - to describe liberal feminists perceived to be intolerant of conservative views - has mushroomed, he suggests.

Mr Godwin says those who label US President Barack Obama a Nazi in response to some interventionist government policies fail to appreciate the absurdity of the suggestion.

"People are driven to make extreme comparisons because of the intensity of their feeling," he adds, suggesting the economic situation has added to those pressures.

As a commentator with a libertarian bent, Gaunt might not seem to have much in common with former London mayor, and left-winger, Ken Livingstone.

But Livingstone also found himself invoking Godwin's Law when he told a Jewish newspaper reporter he was "just like a concentration camp guard".

Reflecting on the incident this week, Mr Livingstone remains unrepentant.

People use the term for impact but it's wasted - people focus on the word, not what's being said Jason Vit

"[A]ll my life I have lived in a country where people say 'jumped-up little Hitler' and 'behave like concentration camp guard'," he told the Evening Standard newspaper.

"They have entered the popular culture. You are suddenly told you can't use these terms."

Whether or not such comparisons have become more unpalatable, one expert debater says deploying the N word is just lazy arguing.

"Any time you use an extremist term or insult, you lose both the moral high ground and the debate almost immediately," says Jason Vit of the English Speaking Union, which promotes exchange of ideas through debate.

"Often people use the term because they think it will have a big impact but it's wasted because people focus on the word and not what's being said."

Mr Vit says it is fine to describe an argument as ignorant, short-sighted or pointless - but never a person.

"If you call someone 'ignorant' it means you're no longer listening to what they're saying because you've made a value judgement about them."

And, he adds, it is always better to use words that get across the argument without carrying any "baggage".