Build the tower up, only to knock it to the floor. When my son was tiny, he could play that game for hours. As he got older, often it felt as if I was doing the same.

Childcare for working parents is one huge wobbling Jenga stack, in which someone is always yanking out the brick that brings everything crashing down. Child running a temperature? Crash. Stuck late at work? Crash. But increasingly, what’s collapsing it is the cost.

A survey of more than 20,000 working parents, coordinated by the website Mumsnet with 13 other groups, lays bare a broken system. A third of parents spend more on childcare than on their rent or mortgage (rising to almost half of black respondents). The cost of a one-year-old’s nursery place in England rose four times faster than wages between 2008 and 2016, and more than seven times faster in London. But it’s hardly as if the people changing your toddler’s nappies, or teaching them the alphabet, are getting rich as a result.

Wages for early years staff are embarrassingly low, given we trust them with the most precious thing in our lives and that they’ve been on the Covid frontline during the pandemic, something which may help explain reports of nurseries struggling to recruit. As for nannies, even Boris and Carrie Johnson apparently couldn’t afford one; when baby Wilfred was born, party donors were reportedly approached about chipping in.

Somehow we have ended up with a system that’s too expensive for parents (especially single parents) but not lucrative enough to pay staff properly, plus a hidden drag on the economy, as parents reduce their hours because they can’t afford a full-time nursery place. A staggering 94% of those changing their working patterns after having children say childcare costs were a factor; surprise surprise, women were more likely than men to say they’d be more senior or better paid if it wasn’t for childcare considerations.

There’s no money to fix this, obviously; there’s never any money, unless of course the right people start asking. For a decade now, successive chancellors have frozen fuel tax for fear of a backlash from White Van Man, forgoing an estimated £50bn. But if Blue Collar Woman can’t afford to do her job because childcare would swallow everything she earns and then some – well, that’s different. Yes, it’s welcome progress that three- and four-year-olds (plus disadvantaged two-year-olds) can now get up to 30 hours of free care a week. But there’s a worrying gap between what the state pays providers for supplying those free places and the actual cost of doing it, which means free places get harder to find and costs for younger toddlers or parents needing longer hours are pushed up to compensate. Don’t even get me started on the plight of shift workers whose jobs don’t fit neatly around nursery hours, or holiday provision for older children.

All of this has been the constant background music not only to my parenting life, but for decades before that. But something about the current surge of fury – the campaign group Pregnant Then Screwed and Grazia magazine together collected the 100,000 petition signatures needed to trigger a debate on the funding and affordability of childcare in parliament on Monday – feels new.

Millennial mothers are thrillingly activist by comparison with us exhausted Generation Xers. They don’t feel grateful simply to have kept their jobs after giving birth, and won’t be fobbed off with lectures about how they shouldn’t have kids they can’t afford (generally from people who are only here to say it because they were born when houses were so cheap that families only needed one salary). During lockdown, parents came to appreciate the childcare they suddenly didn’t have as never before. But for some, the money they weren’t having to spend on it was also the only thing keeping that precarious tower in the air, and returning to the office will knock it to the floor again. Are we really going to leave it there?