Dr Max Davie, the officer for health improvement at the Royal College of Paediatrics and Child Health, said: “This sharp increase in obesity levels across childhood is alarming. 

“While lockdown may have been a key factor, we mustn’t assume that this year’s results are an aberration since there may be other factors, including mental health difficulties, which will take time to address.”

Officials said that the volume of data for 2020-21 was more limited than that for 2019-20.

The National Child Measurement Programme normally weighs and measures children throughout the school year but, with schools closed for much of the pandemic, officials were only able to restart the programme this March, a year after the first lockdown. 

Diet coaches for young children

A network of specialist clinics is being created amid concern that millions of children are so overweight that it is damaging their health, officials said on Tuesday.

Around 1,000 children a year could be offered diet plans, mental health support and coaching, with specialist help designed to aid those suffering health complications related to severe obesity.

However Tam Fry, of the National Obesity Forum, said such moves by the NHS were insufficient to deal with the scale of the crisis. 

“For two years we have had reports of children increasingly being kept at home because of Covid restrictions, endlessly snacking on junk food on top of the amount they regularly eat at meal times and prevented from being to play with their friends to burn off excess calories,” he said. 

Nikki Joule, the policy manager at Diabetes UK, said the data was “hugely concerning” and “underlines why urgent action is needed to improve children’s health”. It follows warnings that the obesity crisis has left more than 1,500 children with Type 2 diabetes – a condition that normally affects the middle-aged.

Ms Joule said: “The environment we live in is a major contributing factor to rising levels of childhood obesity and, for too long, too many children have been exposed to unhealthy food. 

“Measures such as restricting promotion of junk food and ensuring easier access to healthier food are vital if we are to reverse this worrying trajectory, and guarantee healthier futures for the next generation.”

Amanda Pritchard, chief executive of the NHS in England, said: “The pandemic has shone a harsh light on obesity, with many vulnerable young people struggling with weight gain during the pandemic.”

Prof Stephen Powis, NHS England’s national medical director, said: “These figures are frankly disturbing. Rates of childhood obesity are now at an all-time-high, with many young people struggling with weight gain during the pandemic.

“This is a huge concern for the NHS and health of the nation because, if left unchecked, obesity has severe consequences causing a range of serious conditions from liver problems to Type 2 diabetes and even cancer.”