Until the year 2000, no cases had been recorded in children in the UK, with the condition normally diagnosed among those over 40. But NHS Digital data for 2019-20 reveal that it now affects 1,560 people aged 18 or under in England, including more than 100 under 12.

Children who are severely obese can also develop early heart disease, liver conditions, breathing problems and sleep and mental health difficulties. 

Analysis shows that 2.5 million children in England are overweight or obese, while 1.22 million are significantly obese and eligible for NHS treatment. On Tuesday, NHS Digital will publish new data examining the prevalence of obesity among children.

Last year, Boris Johnson launched an anti-obesity strategy, after saying his own brush with death after contracting Covid last year had made him realise he was “too fat”.

The strategy included plans for a ban on TV and online adverts for food high in fat, sugar and salt before 9pm and ending buy one, get one free deals on unhealthy foods high in salt, sugar and fat.

The 15 new services are based on an existing service at Bristol Royal Hospital for Children, which has been operating since 2018.

Prof Julian Hamilton-Shield, professor of diabetes and metabolic endocrinology at the hospital, said: “Many children and young people with excess weight experience significant complications that can make them very unwell.

“Using a team of experts from many disciplines, including specialist dieticians, social support workers, and mental health professionals, we can pinpoint the exact causes of weight gain and create tailored treatment plans for each child to help accelerate weight loss and address the complications caused.”