The Edinburgh festival fringe has an “appalling” record of sexual harassment and assault, according to a leading union and a workers’ organisation, which say employers at the event do not take the issue seriously enough.

Fair Fringe, a campaign for workers’ rights at the festival, said the event had a huge issue with harassment and encouraged employers to do more to address the issue.

“Employers have a responsibility to provide a safe workplace and that includes tackling sexual harassment, whether it’s by customers, colleagues or bosses,” a spokesperson for the group said. “Fringe employers need to take this issue more seriously.”

The group encouraged employers to create and implement “a clear sexual harassment policy”, including measures to reduce the likelihood of harassment occurring, as well as “a clear reporting process and a system to deal with customers who sexually harass staff”. “All too often festival workers tell us that these policies don’t exist,” the spokesperson added.

Equity, the union that represents performers, said it has been inundated with complaints about sexual harassment from acts appearing at the fringe festival this year.

The union’s industrial organiser, Charlotte Bence, tweeted that workers and performers had been in touch, detailing stories of being groped while working. “The idea that these indignities are something they have to suffer to promote their work is just appalling,” she told the Times. “There’s a particular dynamic at play in the fringe. It’s the extra vulnerabilities of the late night shows. The lack of paid transportation home late at night.”

The Guardian spoke to performers who had been sexually harassed while working at the fringe. At this year’s festival Maddie Ross of the theatre group Girl Code Theatre was sexually assaulted while flyering to promote the show Coming Home with Me, which was a play about sexual assaults in nightclubs.

To promote the performance the group decided to flyer in their underwear on the Royal Mile. Ross says that most interactions with the public were positive but some groups of men would shout abuse, catcall or take pictures. Then, on the afternoon of the penultimate performance, Ross was assaulted while flyering alone.

“This guy came up to me and asked: ‘What’s it about?’ I was feeling confident and told him it was about sexual harassment in nightclubs and he lurched at me, grabbed my arse and said: ‘I’m not surprised you get harassed.’ Before I could say anything, he was gone.”

Ross decided not to flyer again after the incident and said it altered the way she viewed the festival. “I was very angry,” she said. “I saw the irony straight away. It felt ridiculous, this was exactly why I’ve written the bloody play.”

Research conducted by the comedy listings website Chortle from last year revealed that one in four female comics said they had been sexually assaulted while gigging, with one in 13 saying they’d been raped. The research, which surveyed over 300 acts, included anonymous performers recalling stories that ranged from being followed home after gigs and threatened with physical violence to sexual assaults by other comedians.

Some of the alleged incidents – according to the Chortle research – took place at the fringe, including one comic who said they were raped by another comic in an Edinburgh flat. Others reported being physically threatened by drunk hecklers, with one audience member attempting to glass a comic after a show. Others complained that venues did not do enough to protect them or follow up on the alleged assaults.

Fair Fringe said that since a section of the Equality Act 2010 – which forced employers to take reasonable steps to prevent harassment from happening – was repealed in 2013, it had become incredibly hard to hold employers responsible for not preventing third-party harassment.

During last year’s festival several shows took #MeToo as their subject matter and played with the boundaries of gender and sexual interactions. Several comics included details of sexual assaults or harassment in their shows. Rose Matafeo, who won the coveted best comedy show award last year with her show Horndog, included a section about her experience after being sexually harassed by an unnamed fellow comic before a set.

Dutch comic Micky Overman’s 2019 performance includes a segment on her experiences when a male audience member was seen masturbating during her set. “[The venue] were informed by another comic who had seen it happening but, knowing what it means to perform at the festival, did not want to interrupt my show. So he sat through it all, occasionally nudging the man to try and get him to stop,” she wrote for the Guardian. “It made me feel violated, and I worried that he’d come back.”

The Edinburgh Festival Fringe Society said everyone who attended the event had “the right to feel safe and supported throughout their time at the festival”, and that the organisation had clear information on its website for people who need support.

“The Fringe Society takes complaints of this nature very seriously and is already in contact with Equity to better understand the nature of these complaints,” it said. “We would urge anyone who has experienced inappropriate behaviour of this sort to contact Police Scotland directly.”