I recently delivered the annual Adam Smith lecture in Kirkcaldy, Fife. It was the first time a woman had been trusted to give this economics lecture all by herself. As a marvellous bagpiper led the way, it struck me that this might be my glass cliff moment. Because, let’s face it, I’m not an obvious choice for such a task. But with men now making up two-thirds of economics students, all but one of the Nobel prizewinners for economics having been a man and every single British chancellor of the exchequer somehow having been required to be a boy, then finding a woman might have been tricky.

By happy coincidence, I chose as the subject of my lecture women’s exclusion from the formal economy. Or as I like to call it, our grossly undervalued domestic product (GUDP). Never, as it happens, has this been more relevant than now, as the full horror of the gender pay gap is revealed. I have so enjoyed watching the debate unfold. Highlights include accusing women of conflating pay discrimination with the gender pay gap – silly women! – though nobody benefits more from this apparent “confusion” than the companies evading legal action.

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Better still are those bemoaning the lack of explanatory data, while dogmatically concluding that the gender pay gap has nothing to do with discrimination in hiring or promotion decisions. And my absolute favourite – let’s not forget the pro-choicers. These are the three women on this planet whose privilege and adoration of unfettered capitalism leads them to infer that women simply choose to work for less, and guarantees them a slot on every talkshow “in the interest of balance”.

But the pay gap isn’t the choice of women. It is both a cause and consequence of gender inequality. In many respects it is more important than pay discrimination because it shines a light on the deep structural inequalities in every part of our society and economy.

On my way to the lecture, I stopped in at the Cottage Family Centre in Kirkcaldy. This wonderful community service was set up by a group of local parents in 1987 and provides a lifeline to poor families in the area. In 2016 its Christmas appeal provided food and presents to 300 children. By last year as many as 800 children and families needed its help. When they recently learned that they had lost one of their funding streams, the extraordinary women who work there offered to take a pay cut so that their community wouldn’t suffer.

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The Cottage is a stark reminder that poverty is gendered. Most of the people it serves are women and children who have been first in the line of fire for austerity. Because, as Sophie Walker, leader of the Women’s Equality party, has repeatedly pointed out, “while tax cuts are benefiting men, benefit cuts are harming women”. Research carried out by the House of Commons library in 2017 revealed that it is women who have borne 86% of the burden of austerity since 2010. The brilliant staff who work at the Cottage are overwhelmingly female, no doubt encouraged by an education system that says caring jobs are for women, and the scarcity of flexible working in other sectors.

The relegation of women in our economy means that these sectors are always undervalued and lower-paid, despite growing demand. Successive governments have prioritised investment in physical infrastructure (jobs for the boys) while social infrastructure (nurses, for example) is still seen as an expense to be cut. I can always tell our economy is in trouble when I watch the news and see the chancellor of the day put on a hard hat and hi-vis vest to announce some big, butch building project. “We may be in financial hell but look at me handle a brick!” I hope it makes the guy from No 11 feel like he’s doing something, but the truth is it doesn’t even make economic sense.

The Women’s Budget Group has shown that if you invest 2% of GDP in the care sector, you get double the number of jobs compared to the same investment in construction. According to Save the Children, 870,000 mothers would return to the workplace if they could afford childcare – reducing out-of-work benefits and increasing the tax base.

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In his autumn budget last year the chancellor announced another splurge in infrastructure spending to get Britain driving again: transport connectivity, upgrading motorways. On the whole it is men’s jobs that are seen as an investment. I’m not having a go at the right here. I pride myself on being an equal-opportunity blamer. Jeremy Corbyn also pledged a £500bn investment in infrastructure, manufacturing and new industries. Labour’s 2017 general election manifesto committed to nationalising pretty much everything except childcare and social care. They fail to see that the global inequality crisis is a gender inequality crisis.

Our lives are still rigidly divided into economic and social, productive and reproductive, paid and unpaid. One half always has more value than the other. The result is that the redistribution of wealth in this country, and globally, is too often from the poorest women to the richest men. Eight men to be precise – contrary to popular belief, they don’t in fact work at the BBC. Eight white men now own the same wealth as the 3.6 billion people who make up the poorest half of the world’s population. And it is women who are disproportionately represented in the poorest half of humanity.

Yet this situation doesn’t benefit your average man any more than it does the average woman. So if, like Adam Smith, you are a fan of self-interest then you should know that women’s equality is better for everyone. The fact is, more equal societies do better on just about every available metric: mental health, general health, crime rate, education and so on.

Mr Smith, the father of modern economics, lived with his mother until she died. It was her invisible hand, her GUDP, that left him free to write his great works. I think it is now time to honour her contribution too. But, hey, what would I know?

• Sandi Toksvig is a comedian, author and broadcaster. She is a co-founder of the Women’s Equality party