This means more than 26,000 children in England are considered severely obese, which greatly increases their risk of a host of health problems, including high blood pressure and diabetes.
This is the fourth consecutive year that severe obesity in Year 6 has broken records, and it is up more than a third since 2006.
Obesity has also continued to rise among the youngest children in the report, those aged four to five.
The data, taken from the National Child Measurement Programme, showed that the proportion of overweight or obese pupils in Reception Year was up slightly at 22.6 per cent in 2019 from 22.4 per cent the previous year.
According to PHE, the figures were the highest among children from the most deprived areas, where 13.3 per cent of four to five year olds are obese, compared with 5.9 per cent in the most affluent communities.
Obesity prevalence in Year 6 is 26.9 per cent in the most deprived areas, compared with 11.4 per cent in the least deprived.
PHE said the figures showed the “importance of serious action from all sectors, including the government’s steps to tackle childhood obesity, such as its challenge to the food industry to reduce 20 per cent of sugar and calories in everyday foods consumed regularly by children”.
NHS chief Simon Stevens said: “These figures show we are clearly not on track to meet the government’s sensible goal of halving childhood obesity.”
PHE’s Dr Alison Tedstone added: “Severe obesity in Year 6 has reached a new high, putting children at risk of poor mental and physical health, now and as they become adults.”
The report by Davies made a number of recommendations to help tackle the crisis, including a rise in VAT on unhealthy food and extending the soft drinks tax to milk-based beverages with added sugar.
Davies also suggested capping the number of calories per serving for all food and drink served by cafes and restaurants, and phasing out marketing of unhealthy food at all major public venues.