Boris Johnson is allowing a “wild west” culture of misogyny to grow in Westminster by failing to tackle “the arrogance of privately educated men,” England’s only female metro mayor has said.

Tracy Brabin, the Labour mayor for West Yorkshire, said: “The idea that somebody who was elected by the public is watching pornography on his phone whilst being at work – I think it’s an aggressive act in the first instance, because women and others will see you doing that. And it’s an arrogance that they are above the law.

“I think unfortunately it comes from the top. This behaviour will only get worse because of the dereliction of duty of the leader. If you don’t lead with principles, dignity, inclusivity and equality then it’s a wild west. It’s a free for all.”

Her comments came amid renewed focus on misogyny and sexual misconduct in parliament as a string of female MPs came forward with examples of sexism and harassment.

Labour and some senior Conservatives have demanded to know why the whip has not been withdrawn from the pornography watching MP, who has been identified by two party colleagues. The Conservative chief whip, Chris Heaton-Harris, has said the unnamed MP should be referred to an independent complaints process.

Brabin, the former Labour MP for Batley and Spen, is the only woman among the 10 metro mayors in England. She heads the M10 group of mayors, which include the Conservative Andy Street and Labour’s Sadiq Khan, and represents 2.3 million people in West Yorkshire – meaning she is Labour’s most powerful woman outside Westminster.

In an interview to mark her first year in office, Brabin said she felt more pressure to deliver as the only woman and that political parties, including Labour, must do more to get women into leadership roles.

Brabin, a former Coronation Street actor, said she had not directly been subject to misogyny during her five years in parliament because, she said, there was cross-party affection for her after the murder of her friend and predecessor, Jo Cox.

The former shadow culture secretary received a slew of online abuse after wearing an outfit that showed part of her shoulder as she spoke at the dispatch box in February 2020. She responded to her abusers at the time by tweeting that she was “not a slag, hungover, a tart, about to breastfeed, a slapper, drunk [or] just been banged over a wheelie bin”.

She said: “It was really shocking. Not frightening, it was just shocking. Men interpreted what happened in a sexual way. People say about Boris Johnson, or other people who come to the dispatch box: ‘They look tired, or dishevelled,’ but it’s not sexualised. Women are always sexualised.”

Brabin compared sexualised online abuse with the comments by Tory MPs who accused Angela Rayner, Labour’s deputy leader, of using a “Basic Instinct” ploy to distract the prime minister by crossing and uncrossing her legs in parliament.

“That’s what happened to Angie,” she said. “It doesn’t say much about Boris Johnson that his colleagues think he’s so easily distracted he’s like some teenager that just can’t keep it in his pants, but maybe they know him better than we do.”