Doctors have warned that a “truly alarming” lack of access to outdoor space at schools is exacerbating Britain’s child obesity crisis. Child obesity is already a significant public health problem. In England, one in three children are leaving primary school overweight or obese and face a higher risk of serious health conditions, mental health problems and dying prematurely. But medics and public health experts say that poor access to playing fields and playgrounds at state schools is contributing to worsening and wider health inequalities, which is leading to thousands of children growing up overweight or obese. The stark revelation emerged as part of a Guardian investigation examining disparities in access to green space between private and state school pupils. Children at the top 250 English private schools have more than 10 times as much outdoor space as those who go to state schools. Meanwhile children at state schools are facing a devastating loss of space and time outdoors, with experts warning that the problem may be linked to rising numbers of children experiencing mental health difficulties. Dr Kath McCullough, the Royal College of Physicians’ special adviser on obesity, said there was “no doubt” that a lack of access to green space – and the gap between state and private schools – was compounding the crisis. “This huge gulf in access to open spaces at school is another example of the health inequalities facing young people. Merely because of the school they go to, too many children may be growing up in an environment that is simply not conducive to healthy long-term development.” The most recent NHS figures show that the proportion of 10 and 11-year-olds who are obese was 22.7% in 2022-23. When obesity and overweight figures are taken together, 36.6% of children in England are an unhealthy weight. Last year the Guardian revealed how a report commissioned by the government warned that children were likely to develop avoidable life-changing health problems because ministers had shelved anti-obesity policies until 2025. The sustained high prevalence of child obesity was “extremely concerning”, McCullough said, and inequalities in access to green space at schools “compound that worry”. “Over one in five children aged 10 and 11 are living with obesity in England. And we know that children who live with obesity are significantly more likely to live with obesity in adulthood and are therefore more prone to increased risk for diabetes and cardiac problems at a far younger age.” The average student at one of England’s top private schools has access to approximately 322m2 of green space, whereas the average state school student has access to about 32m2 of green space: a ratio of 10:1. Meanwhile, new and unpublished research from the UCL Institute of Education shows that the youngest children in primary school lost 14 minutes of playtime between 2019 and summer 2021 – part of a continuing downward trend. Meanwhile a new Guardian analysis of the space available to state school children in England has revealed that thousands are attending schools with very little outside space, with government data showing that at least 500 schools have less than 1,000m2 and nearly 30 have no outside space at all. At more than 1,000 schools, students have less than 10m2 per pupil. “This is an outrage,” said Dr Jackie Applebee, a GP in Tower Hamlets, east London, which has the highest rate of child poverty in the UK. “The government must act immediately to fund state schools so that their premises are fit for purpose including, vitally, the outside space.” Asked what health harms she and other doctors were seeing in children because of limited access to outside space at schools, Applebee said: “Obesity is the obvious one.” “If schools have restricted outdoor space they are limited in the organised games they can provide. Rugby, football, tennis, hockey, netball for example all require large areas to enable playing. Many urban schools aren’t able to offer any of this.” An inability to learn and participate in team sports makes it less likely pupils will pursue the games outside school, Applebee said, which in turn can further raise their risk of growing up overweight. A lack of access to pitches or courts at school also prevents children from practising their skills and exercising during unstructured outdoor time such as lunch breaks and play times, Applebee added. “Children with only 32m2 miss out on this. They don’t expect to exercise because they aren’t used to it and aren’t able to enjoy it. This embeds into lifelong attitudes to exercise and weight gain.” Prof Stephen Holgate, the Royal College of Physicians’ special adviser on air quality, warned that poor access to green space at schools was also enabling greater exposure to air pollution, which was increasing children’s risk of obesity. “The lack of open, green spaces in state schools is truly alarming. Air pollution – particularly in urban environments – is a wicked problem that has significant health implications. Children are especially susceptible with clear evidence of poor lung growth, asthma and respiratory infection. “For children whose homes are in densely populated, built-up areas, schools that do have open spaces can provide crucial respite from what can be a seriously unhealthy environment. Without it, children can miss out on increased physical activity, improved lung and vascular health, reduced obesity and blood pressure, improved mental health and even higher IQs. “Optimising access to open spaces for children – particularly for those who do not have access to such spaces at home – must become a greater public health priority to protect the next generation.”