A survey of 2,000 mothers across the UK found that after having children nearly half (44%) reduced their hours, around a third left work altogether, and more than one in five returned to work in a lower grade or lower paid role.

Of those who reduced their hours after having children, more than a third (36%) said it made more financial sense to work part-time than pay for childcare, while almost a quarter (23%) couldn’t afford suitable childcare.

The People’s Pension, a not-for-profit provider which commissioned the research, said that childcare costs are widening the gender pensions gap, with the average female pensioner £7,000 a year poorer than her male equivalent.

What’s more, childcare in the UK is more expensive than anywhere else in Europe.

Analysis by The People’s Pension suggests that for a woman in London who earns the median full-time income, with a child under two, 60% of her after-tax earnings will go towards childcare and commuting, reducing her take-home pay to £9,700 per year or a little over £800 per calendar month.

Outside of London the numbers aren’t much better, with a woman on the median full-time salary paying 44% of after-tax income in childcare costs, leaving her with around £13,000 a year to live on.

Gregg McClymont, director of policy at The People’s Pension and former shadow pensions minister, said: “Of course, many women choose to reduce their working hours or leave their job because they want to spend more time with their kids, but our research is clear – the cost and availability of childcare is a key factor for many women.

“If we’re going to tackle pensions inequality, not only are changes to auto-enrolment required but better provision of affordable childcare is a must to enable those mums that want to keep working or work more hours, to be able to.”