The report, shared exclusively with The Independent, also found 45 per cent of mothers are currently working below their pay grade and expertise to ensure work can fit around school hours.
Researchers discovered 48 per cent of mothers feared a dearth of wrap-around care – which refers to before- and after-school clubs for children aged between five and 11 – would stop them being promoted in their jobs.
Rachel Carrell, founder and chief executive of Koru Kids, a childcare service which carried out the study, said: “The school day and working hours just simply don’t add up. Clearly something has to give, and what’s giving way is mums’ careers and livelihoods.
“We surveyed mums because we know that it is unfortunately still mums who are taking on the lions’ share of childcare, a pattern which begins during maternity leave.”
She noted people wrongly presume the struggle to find childcare will end when their children start school, but it can get even tougher for many parents.
“Parents, especially mothers, are running themselves ragged trying to fit their jobs around school hours, unable to rely on the wrap-around care that they need,” Ms Carrell added. “In 2019, Boris [Johnson] promised a £1bn injection into childcare including wrap-around care and holiday clubs, and yet this never materialised.”
Ms Carrell warned the pandemic had brought the childcare sector to “its knees” with parents in turn “paying the price”.
Researchers, who surveyed 2,000 mothers around the UK, found one in five mothers who do not have access to wrap-around care are subsequently forced to work fewer hours.
While 20 per cent of mothers who have no access to such childcare say it has impeded their careers and 16 per cent say it has resulted in them has losing out on a promotion.
Anna Whitehouse, founder of Mother Pukka, a popular blog for parents, said: “What we are asking of mums is mission impossible. Mums are left legging it from pillar to post, from work to school and back again to paper over the cracks of a childcare system that doesn’t work.
“Quite frankly we’re worn out, and as this research shows, we’re stuck. We can’t win. I fully support this ask of the government to level up its support for before- and after-school care, because if we increase funding and support for mums with childcare then and only then will we see a real shift in the gender pay gap.”
The study found one in 10 schools fail to offer any before- or after-school care, while out of schools which do provide it, 12 per cent of parents do not have enough money to pay for it. And 4 per cent of parents cannot get school wrap-around care due to services being overbooked.
Laura Lee Whyte, a mother from southeast London, said she was forced to take a hefty pay cut due to the dearth of childcare available out of school hours.
The 37-year-old, who has a nine-year-old daughter, told The Independent: “After I left a job where I was a marketing manager about three years ago, I took a 15 grand pay cut to be guaranteed flexibility. It was understood I was well overqualified for the work I was doing. I took a pay cut and a demotion. It is frustrating I have had to make sacrifices with my career.”
Ms Whyte, who was formerly a single mother but now has a partner, hit out at the “massive impact” of the lack of wrap-around childcare available.
She added: “It needs to be accessible for longer. Lots of services finish at five. In many industries, if you are a working mum and you finish at 5pm, you don’t say ‘right it is 5pm, I’ve finished’.
“You are expected or needed to pick up your child by a certain time and you have got the inflexibility of not having leeway with wrap-around care. You’ve got the fear of employers punishing you for clocking off at 5pm.
“It is frowned upon and seen as not being able to put in same amount of work as peers who do not have children.”
Ms Whyte noted many working mothers then make dinner, clean, as well as doing childcare when they return home from work.
“But society does not see this as work,” she added. “And then you open your laptop to do another couple of hours more work.”
She argued that if childcare services operated for longer hours in the day at more affordable prices then women would achieve so much more in the workplace and organisations would stop “losing out on talent”.
Ms Whyte warned there is a “rigid culture” towards childcare in the UK – adding that women are routinely expected to do childcare by employers who “never look to fathers to carry the equal mantle”.
She is now starting her own business as she said it felt like the only way to have autonomy over her finances, daily routine, and earning potential.
Before the pandemic the Organisation for Economic Co-Operation and Development (OECD) found the UK already had one of the most expensive childcare systems in the world. Ms Whyte said the expensive cost of childcare is “backwards and shortsighted”.
Researchers found around eight in 10 mothers with wrap-around childcare think they are working to their pay grade or above it.
Meanwhile, over half of mothers warned the lack of care is having a detrimental impact on their mental health, and a quarter said they feel anxious. More than two in 10 said they felt totally exhausted.
Some 15 per cent of mothers with no wrap-around care said they did not feel like themselves, while one in 10 said it causes conflict with their partner over money and collecting the children from school.
The childcare sector has been plunged into further chaos in the wake of the Covid crisis – with a recent study carried out by the Labour Party revealing almost 20,000 childcare providers are at risk of permanently closing their doors within six months.
In what critics said was a major blow to childcare services, the government recently changed the funding model for nurseries, childminders and pre-schools following the sharp reduction in the number of children using providers since the pandemic.