The most scandalous gender pay gap is hidden – and women find out about it too late

Today's feminists need to campaign for their older selves.

Women in their 20s enjoy the best pay equality with their male colleagues in living memory, according to the Resolution Foundation. The pay gap has halved in a generation to just 5 per cent.

That’s the good news.

Unfortunately, the same research found that by the time millennial women enter their 30s, a more familiar trend kicks in. The pay gap rockets. The penalty for giving birth – or being expected to give birth – continues.

But while these kind of findings may leave women quietly seething at their desks, this is the tip of the iceberg for pay inequality.

Take pensions. One of the unlikeliest social media campaigns of the past few years has been Women Against State Pension Inequality (Waspi), a group of women born in the 1950s who have discovered their state pension age was being rolled back, and want compensation.

Taken at face value, it’s hard to completely sympathise with this demand, especially if you’re a younger taxpayer who is expected to foot the bill and may never even get a state pension (you heard it here first).

But the Waspi campaign has become a conduit for a much wider story about women who must rely on the state pension because they have nothing else to fall back on. These are women who gave up their wages to work as unpaid carers, and women who did go to work, but were fobbed off joining the generous private pension scheme. If the stories have a pattern, it is about women reduced to poverty because of misinformation and discrimination for decades of their working lives.

In retirement, the gender pay gap is stark. Women planning to retire this year expected to live on an annual income 27 per cent lower than men, according to Prudential, a private pensions provider. This is even worse than the pay gap they could expect in work.

There are signs that this inequality will continue, or appear in new forms. Auto-enrolment means employers must provide workers with pensions, but only if they earn £5,824 a year, and only if they are directly employed. Women who drop out of work for childcare reasons lose more than their wage.

Meanwhile, self-employed workers are left to fend for themselves. Both men and women suffer from this disparity, but women are increasingly included – 33 per cent of all self-employed workers were women in 2016, according to the Resolution Foundation, compared to 27 per cent in 2008.

The latest generation of feminists have pushed the pay gap up the agenda again. But if they don’t look at pensions soon, by the time they discover this inequality, it may be too late.