David Clementi says politicians and social media organisations need to do more to stop ‘explicit and aggressive’ behaviour.

Politicians and social media companies must clamp down on the increasingly “explicit and aggressive” abuse suffered by BBC journalists, according to the chairman of the public broadcaster.

David Clementi said it was unacceptable for politicians to “stand by and watch” heckling at press conferences and said the corporation’s female journalists in particular were being targeted by abusers on and offline.

Speaking at the Royal Television Society convention in Cambridge, he said: “Speaking to our journalists, I have become increasingly aware of the abuse that some of them – particularly female journalists – are subject to on an almost daily basis.”

He did not name any of those targeted, but Laura Kuenssberg has frequently been targeted with sexist abuse online and the broadcaster is understood to have given her access to a bodyguard during the general election campaign.

The BBC political editor was hissed at and booed at Labour and Ukip press conferences this year and has received criticism from Conservative supporters, with the Daily Telegraph asking if she is the “most divisive woman on TV today”.

In his speech, Clementi said some of the abuse occurred “in plain sight, at press conferences and political gatherings on all sides.

“Politicians cannot stand by and watch – they must confront any abuse, and make it clear that it is intolerable,” he said. “The journalists of the BBC, when abused simply for doing their job, should know they have the determined support of the board to stamp it out.”

As well as calling for politicians to stand up against the abuse of journalists, Clementi called for Facebook and Twitter to do more. “These days, there is much more abuse. It is increasingly explicit and aggressive, and much of it occurs online,” he said.

“I welcome the work the government is doing to tackle this, and I’m following closely the efforts of Twitter and Facebook, amongst others, to clamp down on the perpetrators. I hope the social media platforms do even more.”

Other BBC journalists who have been subject to abuse include Emma Barnett, the Radio 5 Live presenter, who was sent antisemitic messages after she tripped up Corbyn with a question about the costs of a childcare pledge.

Clementi also tried to address the growing controversy about the gender pay gap and diversity at the BBC, and the prospect of stars disappearing from its list of top earners next year because the shows they work on are produced by BBC Studios, which is classed as a commercial entity and will not have to publish how much it pays people.

The list of the BBC’s best paid onscreen stars revealed just a third were womenand the top seven all men. However, Clementi insisted the BBC was “one of the most diverse workforces in the UK” and said he was confident the gender pay gap at the broadcaster was likely to be “significantly ahead of [lower than] the national average”.

He said: “The targets we have set ourselves to reach by 2020 are among the most ambitious and stretching of any organisation, and we are making significant headway. But we are acutely aware that there is much more to do. Not least on gender.”

More than a third of the BBC stars earning £150,000 or more – including Claudia Winkleman, Nick Knowles and actors from EastEnders, Casualty and Holby City – could disappear from the pay list next year due to BBC Studios programmes being omitted.

This has prompted calls for the government to force the BBC to include these names, but Clementi insisted their omission was fair because BBC Studios needed to be able compete with other production companies “on as level a playing field as possible” and potentially make shows for other broadcasters.

“This exemption is not, as some have described it, an inadvertent loophole,” he said. “It is an integral part of the competition arrangements and, so far as the BBC board is concerned, is an important point of principle.”

Clementi hit back at calls from Karen Bradley, the culture secretary, and private TV and radio companies for Ofcom to introduce more quotas on the type of content the BBC should broadcast, such as religious programmes and news and current affairs. Ofcom’s draft operating licence for the BBC, which is due to be finalised in the autumn, proposes cutting the number of radio programming requirements from more than 200 to 20.

“I am concerned about quotas that relate to hours of broadcasting, since the driver here is around quantity not quality,” he said.

“A charter which places distinctiveness at its heart and then backs it up with a licence full of hourly quotas is a contradiction that is likely to lead to failure. Quotas relating to resource, and in particular to financial spend, are likely to be better drivers towards distinctiveness, although even they can never be guarantors of desired outcomes.”