GB News breached the broadcasting code when it allowed Naomi Wolf to repeatedly compare Covid-19 vaccinations to mass murder without being challenged.

The US author made an appearance last October on GB News’ Mark Steyn show and claimed that the vaccine rollout amounted to a premeditated crime, saying it was comparable with the actions of “doctors in pre-Nazi Germany”.

On Tuesday the media regulator, Ofcom, said it was particularly concerned by Wolf’s “significant and alarming claim” that mass murder was taking place through vaccinations, which she repeated three times without significant inclusion of challenge or context.

In its defence, the channel argued that its audience had different expectations because “GB News has a different approach from many other factual channels”. The channel said it promoted “controversial and contrarian [views] as a way of provoking thoughtful questioning and debate and re-evaluation of important issues”.

This is the second significant breach of the broadcasting code recorded by GB News and the media regulator is requesting the broadcaster attends a meeting “to discuss its approach to compliance”. However, there is no indication Ofcom will impose a financial penalty as the regulator struggles to deal with new upstart channels pushing the limits of the broadcasting code.

GB News also argued it did not defend Wolf’s views as the “literal truth”, but her comments were protected as freedom of expression under the European convention on human rights. It also said that as a Jewish woman Naomi Wolf believed the comparison with doctors in Nazi Germany was “not excessive and a reasonable comparison”.

The channel argued it was a mistake to claim that “outspoken and combative language advocating a view that seems outside the bounds of ‘polite discourse’ must be harmful in some way”. It considered the statements made in the programme “might, at the most, have given some viewers ‘pause for thought’ about the wisdom of having another vaccination” but maintained that this was “part of the value of diverse opinion and in any case cannot be considered in isolation”.

It comes two months after the watchdog ruled an episode of the Mark Steyn show which aired last April broke its broadcasting rules and was “potentially harmful and materially misleading” with an “incorrect claim” that UK Health Security Agency data provided evidence of a “definitive causal link” between a third Covid-19 vaccine and higher rates of infection, death and people being admitted to hospital.

Ofcom said of the latest investigation: “It is important to stress that in line with the right to freedom of expression, broadcasters are free to transmit programmes that include controversial and challenging views, including about Covid-19 vaccines or conspiracy theories. However, alongside this editorial freedom, the broadcasting code imposes a clear requirement that if such content has the potential to be harmful, the broadcaster must ensure that its audience is adequately protected.

“Our investigation concluded that GB News fell short of this requirement by allowing Naomi Wolf to promote a serious conspiracy theory without challenge or context – for example through other contributions in the programme or by the presenter, who appeared to support many of her comments. There was also no scrutiny of the evidence she claimed to hold to support her claims.”

Ofcom said it received 422 complaints that alleged Wolf’s comments were “dangerous” and included misinformation that went unopposed.

The regulator said it recognised the author’s right to hold her views and opinions, GB News’s right to broadcast them, and its audience’s right to receive them: “We emphasise that the code does not prohibit these views and opinions from being broadcast. However, defining content as opinion does not remove the requirement under the code for the broadcaster to ensure that audiences are appropriately protected from potentially harmful material in this programme.”

Steyn quit GB News in February after the channel tried to make him personally responsible for any fines levied by Ofcom against his broadcasts, having repeatedly railed against the media regulator and claimed it was acting as a state censor.