Laura Bates, founder of the Everyday Sexism Project, singled out Ryanair’s advertisements featuring cabin crew in bikinis.

“It’s like you’re buying access to the air hostess as part of the fare,” she said, adding that images like this “encouraged the sexualisation of travel and women in the industry” and facilitated unacceptable behaviour from holidaymakers.

Another image from Florida’s Spirit Airlines featured the acronym “Milf”, which was displayed as Many Islands, Low Fares.

Meanwhile, Bates showed a series of images of Virgin Atlantic founder Branson surrounded by a group of female flight attendants. “It’s a clear message that companies themselves endorse this. That makes it difficult for women to speak up against it.”

The Everyday Sexism Project (everydaysexism.com) encourages women to report on its website what had previously been seen as minor incidents of discrimination and abuse. In its first three years, the site has attracted more than 100,000 stories. “You can’t set out to solve something if people do not acknowledge it is there,” she explained, adding that the “vast majority of men would be shocked how common it is”.

Bates also discussed sexism within the workplace, describing it as “really quite low level and subconscious”.

She added that there was a problem of under-reporting, normalisation and acceptance, and advised against a heavy-handed approach by companies when dealing with things such as inappropriate remarks.

“It does not have to mean a massive serious intervention, it really can be in a very light way; just mention it when it happens. It’s not about a witch hunt, it’s about weeding these things out.”