Parents face bills of at least £39-a-week for uniform, supplies and transport to send children to secondary school, new research shows.
Analysis by the Child Poverty Action Group laid bare the strain on family budgets, leaving some parents forced to choose between paying bills and buying kit.
State education is free but the cost of uniform, learning materials, school trips, packed lunch and transport sets most parents back at least £39.01 per week per secondary school child and £18.69 per primary child.
This tots up to an annual bill of £864.87 for primary pupils and £1,755.97 for secondary kids - excluding childcare and at-home costs like printers.
Over 14 years of schooling, the price tag rises to an eye-watering £18,345.85.
Kate Anstey, head of CPAG’s Cost of the School Day programme, said: "Parents are guilt-stricken when their kids are left out at school but when you can’t cover the electricity bill, how is a new PE kit affordable?"
Uniform - including PE kit and school bags - is the biggest cost for parents of primary kids at £352-a-year, and comes in at £481 for second school children, second only to transport costs at £487.
Packed lunches set both primary and secondary school families back around £350-a-year.
It comes amid mounting pressure on the Government to offer free school meals to more needy kids.
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The Mirror is campaigning with the National Education Union for free school meals to be extended to all primary school pupils, regardless of household income.
Ms Anstey said: "Our research shows there’s a hefty and often hidden price tag for just the basic essentials needed for school. For struggling families it can feel more like pay-as-you-go than universal education.
"It’s on each national government to intervene and ensure that every child has at the very least the essentials required to take part in school and learn.
"Without that intervention, the very idea of universal education and equal life chances for children is undermined."
Paul Whiteman, general secretary at school leaders’ union NAHT, urged the Government to extend free school meals to more needy kids and take action to address "shameful levels of child poverty".
He said: “Children who arrive at school hungry, cold or tired cannot focus properly on their learning and our members are increasingly having to go above and beyond to help struggling families by providing basic necessities. But this isn’t sustainable, especially as school budgets are also under considerable pressure.
“The government needs to do far more to break down the barriers to children’s learning caused by poverty, which are now affecting many more families due to the cost-of-living crisis."
Dr Mary Bousted, Joint General Secretary of the National Education Union, said children in poverty were facing barriers to their learning.
"While our members work tirelessly to ensure that all children receive the education they deserve, rising child poverty and a cost of living crisis is making that harder," she said.
"Schools need the funding and the support both from within the school and from external organisations to ensure no child is left behind."
A Government spokesperson said: “The Government is committed to finding ways to mitigate rising costs to ensure that uniform, food and travel costs are never a burden for parents or a barrier to pupils accessing education.
“Over a third of pupils now receive free school meals and we have also extended the National School Breakfast Programme for another year.
“Through the Household Support Fund, we have also provided an extra £1billion to help the most vulnerable with essential costs including food, clothing and utilities.”
