Channel 4 chief executive Alex Mahon has said the Russell Brand allegations show that “terrible behaviour” towards women has been “historically tolerated” in the industry.

Ms Mahon addressed the claims against the presenter, who used to host Channel 4’s Big Brother spin-off shows EFourum and Big Brother’s Big Mouth, as she opened the Royal Television Society (RTS) Cambridge Convention on Wednesday.

Brand has strongly denied the rape and sexual assault allegations which span between 2006 and 2013, when he was at the height of his fame while working for the broadcaster, BBC and starring in Hollywood films.

Ms Mahon, who is also the RTS convention chairwoman, said in her opening speech: “The allegations made against Russell Brand are horrendous and as a CEO of Channel 4 and as a woman in our industry, I found the behaviours described in Dispatches and The Sunday Times and The Times articles disgusting and saddening.

“The allegations of course need to be followed up further and we and the BBC and Banijay are busy investigating.”

She added that her channel had invited anyone that knew about such behaviour to come to them directly, as well as noting that they had set up a process for people to contact the broadcaster anonymously if they needed to.

“They are not empty words or gestures from all of us, they are what is meant by our duty of care”, she continued.

“We will seek to find out who knew, who was told what and what was or wasn’t referred up.

“But what is clear to me is that terrible behaviour towards women was historically tolerated in our industry.

“And the clips as well provide a rather very shocking jolt when one realises what appeared on air not that long ago.”

Ms Mahon said the behaviour was “less prevalent now” but recognised it was still a problem and something broadcasters must all confront.

“There is still more change that needs to come and Channel 4, along with those others, are at the forefront of that change”, she added.

Alongside the Channel 4 and BBC investigations, another investigation is being conducted by Banijay UK, which bought Endemol, the company commissioned by Channel 4 to produce the Big Brother spin-off shows the presenter hosted, into his behaviour while he was working on its programmes.

Culture, Media and Sport Committee chairwoman Dame Caroline Dinenage wrote to broadcasters on Tuesday, including Channel 4 and the BBC, to request further details about what actions they were taking in response to the allegations and for a timeline on when their investigations would be completed.

In a letter to the Commons committee on Monday, and published on Tuesday online, Ms Mahon said: “Since becoming aware of some of the allegations, just over a week ago, we have carried out extensive document searches and thus far have found no evidence to suggest the alleged incidents were brought to the attention of Channel 4 management at the time.

“We will continue to look at this issue and will forensically examine any further information, including the accounts of those affected.”

On Tuesday, both video-hosting site YouTube, which hosts Brand’s channel, and podcasting platform Acast, where his Under The Skin podcast appears, said he would not make money from advertisements on their sites and apps.

During an RTS session about the abundance of content globally which Ms Mahon chaired, she asked the EMEA vice president of YouTube, Pedro Pina, to clarify how turning off the monetisation would affect Brand, to which he replied: “Essentially, he’s not able to make a living through YouTube.”

He added that it would not make an impact on the prioritisation of Brand’s content on the platform as he explained this process was not connected to how they recommended videos based on users’ interests.

Mr Pina continued: “We don’t tolerate harmful content inside the platform. Right now, from what we know, we don’t have harmful content by Russell Brand at YouTube.”

He explained that had previously taken action when there was an incident surrounding “medical misinformation”, adding: “If we find out over the next days, hours, weeks, that there is more reason to take more action, we will.”

Last year, one of Brand’s videos was taken down on YouTube over the site’s policy on Covid-19 disinformation, which prompted him to move his channel to Rumble.

Brand vehemently denies the allegations brought against him in a joint investigation by The Times, Sunday Times and Channel 4’s Dispatches, which also include claims of controlling, abusive and predatory behaviour.

In a video posted online on Friday night, Brand said he had been “promiscuous” but that all of his relationships had been “consensual”.