The story of the receptionist who was sent home from her temp job at PwC in London because she wasn't wearing heels sounded incredible to most people. In 2016, here we were, discussing whether or not a woman should be forced to wear high heels in a bid to satisfy some outdated notion of what constituted smart office wear.

After listening to Melissa Di Donato, a vice-president in multinational cloud computing company Salesforce, the idea doesn't seem all that incredible.

“When I was starting in my career I remember my mentor, who was a man, saying you shouldn’t wear trouser suits, you should wear skirts,” Di Donato recalls. “It wasn’t that long ago. I didn’t think to myself, I have to wear something just because I’m a woman. I just did it.”

It was only about five years ago, though, that she realised the extent of the issue. It was a request from former IBM chairman Larry Hirst that she attend an event.

Di Donato initially turned down the opportunity to go. “I told him, ‘No, I don’t do women’s lunches’.” But he persisted, and eventually she agreed to go – begrudgingly.

“I had the most amazing experience, and the most transformational experience,” she says. “We heard about entrepreneurs, we heard about business leaders, women who struggle, women who lost, and won. I left that meeting thinking, holy crap, we have a huge problem.

“From that moment forward, every meeting I went into I realised I was the only woman in the room.”

That the tech sector has a diversity problem isn’t news. There have been endless column inches devoted to a lack of women at leadership levels in major companies, and how that problem can be solved.

And yet there still persists the notion that women no longer need feminism or advocacy; that the job is done and there’s a bit of a fuss over nothing.

Not so, says Di Donato. She recounts an experience where she was speaking at a dinner for bankers and venture capitalists: “I walked in and went to pick up a glass of champagne, and a gentleman said: ‘Great, the birds are here’.

“The birds are here,” she says in an incredulous tone. “I asked if he was talking to me, and he said: ‘Oh, right. The event you’re going to is probably down the hall’. I told him I was speaking at this event.”

Out of tune

“I thought, how in today’s world is this actually happening, to me? Is it the way I look? Is it that men are out of tune? That the environment hasn’t really changed? Maybe my heels were too high?

“We are still faced with incredible situations and incredible adversity that you just don’t think are still mainstream,” she says.

Tech may have a diversity problem, but as Di Donato’s experience outlines, it is much wider than that. It’s a business problem – and one that needs to be tackled.

Di Donato is on the steering committee for the 30% Club, an organisation with the goal of having women make up 30 per cent of the boards of FTSE 100 companies. The figure is currently 26 per cent, still below its target but more than double what it was when the group was founded in 2010.

But closing that gap won’t be fixed solely by talking to women about it. Di Donato is very clear: we need to talk to men, not in a subservient way, but in an inclusive way, and in such a way that men understand the value and benefit of diversity.

“Every time we have a meeting, campaign or speaking engagement, there are men always included,” she says. “One of the problems is at a lot of the events I get to speak at, I look around the room and they’re all women. We don’t need to talk to each other. I’m telling you a story that you wrote the book on. We need to be speaking in that room with men.”

She outlines a 2014 Credit Suisse study, which concluded that firms with more women in top management positions delivered higher returns on equity and higher dividend payments than those with low female representation.

“It will improve interaction with customers,” she says. “You’ll get new diverse ideas when you’ve women in the boardroom. Period. There’s statistical and empirical evidence to prove it. I think we need to focus less on the personal side – ‘Oh you’ve got a daughter, do it for her’ – and more on the empirical evidence. It will change your business.”

Avoiding the ‘trap door’

Getting women into those leadership roles needs some concerted effort. Di Donato notes that you need to get women past the “trap door”, that point where they fall behind as men accelerate in the career race.

“We want to solve the problem of more women in the boardroom,” she says. “You can’t do that overnight. We’ve got to shift the paradigm to fill the pipeline to get them into the boardroom in the first place.”

Di Donato doesn’t blame childcare issues for the fall-off rate. As a single mother to a two-year-old, she has first-hand experience. But she is scathing about the term “work-life balance”.

“You have one life. Work has to fit into your life. This is not work/life, this is life. Make it fit in a way that’s appropriate.”

Di Donato says a lot of comes down to confidence.

“Women don’t raise their hand enough to want to excel and make themselves as visible as men,” she says. “I think the best thing as women we can do for our girls is to make sure they grow up in a household and environment of great confidence. Confidence will build strength, strength will build careers, careers will build positions, and we’ll have more women in the boardroom.

“I hope that we continue to instil that level of confidence, because it’s transformative for women.”